Visit gift.climeworks.com/numberphile and us se code NUMBERPHILE10 for 10% off your purchase (sponsor) More videos with Neil: bit.ly/Sloane_Numberphile Prime Playlist: bit.ly/PrimePlaylist
@numberphile hey! I saw this and thought, "what about concatenating increasing values to the left" i.e. 1,21,321,4321,54321, etc. Did a little bit of number crunching and the first one I found was at a starting value of 82. They exist! (I was able to speed up my search realizing that 2/3 of these are divisible by 3 and skipping testing those.) Maybe look for the next one and make a video on it? Prime related videos are always a hit. :) Anyway.... Loved this video! It inspired the little search I just did.
Wouldn't mind them being called Falken primes if there's no name yet. I'm looking into other patterns that I'd be more keen to get something published for. I didn't look past 82. Reason being I typed the number manually into an online primality test. I was more than happy finding 1. (I was willing to go up to 100) I really need to code up something to do these things for me :)
The largest prime that I know the digits of is Belphegor's Prime: 1 0000000000000 666 0000000000000 1 Thirteen zeros before and after the number of the beast, 31 digits (13 reversed) in all.
@@michaelsmith4904 the smallest prime after this one with 13 zeros is with 42 zeros (10000000000000000000000000000000000000000006660000000000000000000000000000000000000000001). also no zeros (16661) is also prime
@@Anonymous-df8it I think 1729 was meant to be a reference to a mathematician just like the 1729 in my username. Still agree that base-6 would've been better than base-10
I got curious and decided to try this - but with base-2 instead of base-10. And I think I found one! 01101110010111011110001001101010111100110111101111, which is 485398038695407, _is a prime_. And it contains the numbers from 0 (which might as well not be there) to 15.
Few others: 1 2 3 4 5 10 11 12 13 14 15(b6) is 4060073996291 1 2 3 4 5 6 10 11 12 13(b7) is 131870666077 12(b3) is 5, 12(b5) is 7, 12(b9) is 11, 12(b11) is 13, 123(b8) is 83 12345(b12) is 24677 (couldn't find anything in base 4) Binary goes till 15 a multiple of five, 3 and 12 both go till 5. 12 and 5 together remind me alot of the golden ratio
I'm intrigued by the sequences both so important and so hard to evaluate that they have the privilege to be included in the OEIS with only one entry. Tell us more about that please !
Someone else in the comments went and found all the one-term sequences on OEIS: A058445, A058446, A072288, A076337, A115453, A118329, A122036, A144134, A245206
I would like to note that if the step between each number is 2 instead of 1 (so 135... instead of 123...) the first prime is 13, but the first interesting one is 135791113151719
I am still contemplating whether this is is an ingenious and pragmatic idea of just writing the contents of the stacked books on the side of the pages or the laziness of not getting a proper bookshelf and organizing the books where you can read the actual titles.
Huh, this is interesting... I actually got 2 "most wanted primes" in hexadecimal with n < 1000, the first is 123456789ABCD (n = 13) and the other is much larger (n = 211)
Curiosity and hard work and persistance are the key in any success in any field. Neil Slone has these factors and more. His achievments in many fields are truley remarkable. He is an Artist in my opinion. Thank you.
Thank you to Numberphile for showing me the beauty of mathematics. I was in high school learning algebra when I was also watching Parker et Al and understanding little, but appreciating the beauty seen by the presenters. Thanks Brady.
So why did Armand Borel want a prime of 20 or more digits? What was he planning to do with the answer? We never found this out. (BTW, is Armand related to Emile Borel of the Heine-Borel Theorem?) Fred
In base 3, not in OEIS, for most wanted primes (or pseudoprimes), you have: n=2 12 5d n=5 12101112 3929d n=82 121011122021221001011021101111121201211222002012022102112122202212221000100110021010101110121020102110221100110111021110111111121120112111221200120112021210121112121220122112222000200120022010201120122020202120222100210121022110211121122120212121222200220122022210221122122220222122221000010001 112472248900628264609109603739848048285897664360560828256938844196881901607705808202739737387845865591848483833175481611716989149644798597217d n=2546 12...a 17096 digits base3 number and in decimals: 438901614887514605466267024386135650600033362816444496806711372482245146884915386909751348997365801080402351449028502471242758888291675821118882089624318810691875547196735723240044009073427703696943580508956388470243977950109715055427911971938769774537861003809418719662224703232659963740936759146413626780864259526623534809268264284464067573779632781576662014162616826112288023392384774287767276320175409899881761958681471740412391874176042195430070221392433210585775906449594019840671917690306383887269066440280869038221590800757726038419310165765817602141383203628163030486797195470487225017025556330003905306893745165136800294081763649102929942289549029289694486589044625755773540712708002139120512015235073943656831115285653411989128764226947221449296389459674032450987082484043225302027278826769410720791535692229493371031924259660556848144314000445654512658136867612154055336435117898846176463282467432817204323281940956831945877855475081487734707725937382588017637605467946620737185161919285910727346515604035560027325241617303161426862687582608779165975115120037965282740364477929244994948643424406776025837599317893217934242983173962854495549552925865358362160216170232431412501191185122859465062497612933449290017800399832615920842635549143644417498407282164430111190673427067279254777126182311689788339580626526879218126104793463452645047651100305200749754425281186984457004839397827526097260844873083759672695142118136400187418757225802418639267030503007125458153523931207934882184132836181235705883074168544338649964944315222818030304854865580595027150897598524505443395177578042859671886994011148667288767765497566847363098520947250508659308001673701049339493880352430223893633783346800139234340664168619262580858161177425052811238334058093109643234935631893615271178784996590633473073045834020706511677721803088305408381234753514475074849924505207886445911252646076120937379014709441628137808976455481463512462096244860345574315484717207832106753890953713937904982858926361286681194513782402190772071347397526087851818679282636863859352153479144525826571420850114077385592124609592686912007702391578702044511649340622136791579272315034250821418780278111935666966091650914548744757218825982833851583002407620557942660474959299938188913070125916269693012051653447069343388401733199482657537411375249202481112064910061966524173074310317506995281791854589825621338034046854382960671569788537973365456474490252399919779987126977112652497293767434735550597779641352914431817257830567295527502994243084492733418360365813514813082113397034621711820937265302372631858924981012233776155001023122872486769362546086022299511589199892237656094464364795419166791495343658971827297078230172672836473972499001793841210218983321833999585865141748945016812805554163352422570692230543971779497512947313915747863897248386240199933836536897429460817607741096407421334176965826575305909098151797856352021065933462319015038571632310281363782242405456561072660828085094572441184322043645967483835458792958061179945950237724064153512479640307650520223071942459696844558775725210873435662497329528062699343340547057845708465401419776666473542234739723112889506098158607358386544763603846912596365421297389929873804176039812718462615217865889168346463573509340991263267280750673373227985960761895444868329529202641984260680399880681697432376882093710003142346365239061028260990115196961790036303028664916802952870971285513130323212935759290243064700926865580807469522757708352423605709300452286552045763227345233428490525305459744051993431832215900878592453007640782228628152888142077344423394604330124218565464396362665619752655039630661092370763799913933061323982754470390704248673099689879044276844231827028973814330989322247881462852458897210262545089984831435951988634241204306544509757730686037451417570579775944158145869252098883388942146173429252051567573522530401013328583210415168947591395744568986130643890797364875606647394354008687467026202990068615725771510886684287497054500143293853741651016641308994226911706619201023960034111577893632812444224116002475647496979880940952622185932420442791808235729577171091700569556999147247238281651414307698923457125018811089030223204213471009151245308726594039942960381506400657188276351996631909496469878494341455015096590860152630086653717147052776243974920863565048770745598343350054367339632222613376129845660848073595236733729148394330150182049430153303525996965101223460297494682810714347238975208847007091915138622524610069828844642103031475682537518816620566074664714010706389507184773671166591423641463947926995682244260517480096043234676623274797478805714178010262597943473907308497240192380947608952606270183913576744271001425297221800285990491194478490872941695038781616831946021363754717166665253777716708699184844182295821946390662947508525762189741247458205462637573773038284499995562162498922657257206676548110378420888182630953507930913936162407326012853951844070139467437286092579039772558117128286112038515914839702812823662723874760982499647832179622468735509287014228638815604389024221105353488557697150202057253599945724951028100136398437626228243145428785211412623961388893948697191179006369598767232091215109668854155733795448325845458855959085896101726236478860711044573327536899308364702654108310850277643652514439466404599781514526217602434435680426173237299033136558608105430552125179732593145895855597822806797138423311127513999228141629403521076652240902990808957938670382742930185334263135596714938518686636870359196417050573013555235794819551427444692941136083169437591866053007429101593174752126422267978113947477461632199149574653056995580876468468841512503929265973642142521433783910029701927589568500637598930280799274868655321543428664359831794693822872073190107789469188420594776959536133518213026753649027479520105658505413112757606653778202698386410866669261793298774706466885673703937418813676083119806154269281559939970261119267626636028263921354951358586526357005123308387086908417130065448016969108814742360412546524023100394681035588457758593149829172706208635924807614988395060367385862447528343392322877668590782646462344060192295581656854743315229508080164680704886014611609639080074611150823795908462622284834799780945214780191321575682473098064219102968720714852110768382124024146577003342386825675534120496009149228085797296664947944284459504397362452714225723572952593450824965261345076198411518594355426018167169450570770204353854645929652792627529836025959158795973160711218806372062533011369683801669606973011385261374554712435374666368510832811165374881024432000630156605745731583527568393362099773864654120614392695816927962941961796870705942732062535883974671407701948049998941787677650275837941332147758540549249531205174662609789801130837306242411970101356781854729807193025032643207669020507166841929182848376450424724622565875933484459506081841788009168152121665356137035803619457997587710285070757557475765648197708197336087442233922801051363259058752900768683917817182530781428990233345335491142657554109362089599381648594598632774233042003995246686666171131041962498052053228777886538814004715290787801519670265151626279751436930607755928758779163379959620642739702102423695906633503666884625284074280469791454947762620400566495649335900149037140329044014471637556290564558780455387345220647032374269572508607146969505876102860307439372051463537783921506332039856547516566554110952445716883101947268480724546997982934076279121300134492266584776249333628351423955196946299312750470582678826773819518561854467008142897111691746984665531975523818102531728930681386711149231763248034500067381101184802415913930239273387662235502940626366340343163935252168633269489942804045742529029442688139410283913282798340772808136427200494607809568040254992549523782574468108842177788575245592080095055866273313609298194731956478946627062925151259845335958921788510456102392365071680602249026359659326337432520150462066773815872963830090143826783584318752589919934485486220644252851108622731473363199478507094210005490820523950776749019625467113947559352128569732955675193115243144136506697105041288337632419988844340393521444498029143167750726032348124797660335107
@@GodwynDi If you have any sort of stem degree, then you probably know (or knew at one time) enough math to do it. I assume you would: look up "distribution of primes", find an approximate distribution of these numbers with a simple form - which looks easy, then determine if the sum of expected number of these primes computed from those results diverges - which could be difficult but is probably very easy. That is assuming of course that there is nothing "special" about these numbers in relation to primes, which seems very unlikely given the form of the numbers.
@@jmodified I probably could have when I graduated college, but that was near 20 years ago. And I don't use any complex math anymore. Still enjoy following the stuff though.
Well, the number of primes like this will be an extremely small subset of all integers. But, since there are an infinite number of integers, any subset with members that occur periodically would, by definition, also be infinite.
2:40 Ten works! And 2,446! And beyond that we don't know... But we DO know there are an infinite number of them! And THAT's why I love Numberphile so much!
Well, to be fair, we don't KNOW that there are any more, we're just assuming that because it's a completely artificially constructed number so it's equivalent to picking at random (taking into account things like the numbers not being even etc) and we can calculate the probability of a number in a certain range being prime so we can calculate the average amount of primes in the first n numbers of the sequence and it diverges therefore one could say it's probably infinite
Very base-10 heavy. The number 12345678910987654321 is indeed very memorable, and a nice piece of trivia at a party, but it seems like nothing particularly special because the fact that we write in base 10 is so arbitrary. I'd be curious to know if we wrote in base-12, for example, or base-n, whether either palindromic sequences or sequences that stop at n would be prime.
I feel the same way about 3301 and 1033 both being prime. Neat fact, but not very meaningful. People easily conflate the properties of the *representation* of a number, with the number itself (I think partially because people aren't taught much about other notations in school, especially other bases.).
This is related to recreational mathematics. You don't seek for beneficial in math at all, problem is problem. The number is in base 10 but It is not true that these problems are not important mathematically.There are serious problems in recreational math and the way to solve them sometimes lead to important areas.
Its possible there an infinate many, just very rare. First counter example could be say n = Gogulplex (well heristically) and occur with probability 1/log_gogulplex n We'd never find one of that were the case
@@Anonymous-df8it You can't prove that this puzzle is unsolvable, because if there is such a prime, then once you know the example, it's trivial to prove that the puzzle is solvable, therefore, your "proof" that the puzzle is unsolvable proved that there is no such prime, which solves the puzzle and contradicts itself.
Spent some time working out a formula for the amount of digits of the number resulting from writing 1 up to n and back down to 1 written in base b. d(2*n+1)-(2/(b-1))(b^d-1) where d = floor(log_b(n))+1 or in other words the amount of digits of n when written in base b
at 3:15 I was just looking at the large number and i noticed one of the lines (starting with 646645) ends with ... 276 266 256 (next line): ... 246 236 226 216 ... and more increments of 10. Isn't it cool that with three digits going one step downwards on each number if you look at it moved by one it goes down by 10? just a random musing, don't mind me haha
To speed things up you can assume the number Must not be Even Or end in 5, It must also not end in any N=3(x) as (N-2)+(N-1)+N Where N is a Multiple of 3 Is Also A Multiple of 3 (as 3n-3 is a multiple of 3 For all whole solutions). This Eliminates quite a lot of numbers
What does the most want problem look like in other bases? Partial answer for base 2 n=15 (1111) Is prime (1101110010111011110001001101010111100110111101111) (485398038695407)
I think I found a “Parker Prime” for you! If you write the numbers from 1 to 121 side by side and treat it as a long decimal number [which would likely too big to visualize in the observable universe] then that number's smallest prime factor is 278,240,783 [more than 80% of the American population]. Enjoy! :)
I wonder if the 1 .. 10 .. 1 prime works for every base you write the number in (like stopping when you reach the base). It seems to work for base 2 and 3
It worked for 4 but failed on 5, from my test. I might have messed up and it was a quick n dirty test and some of my tools might be bad, but thats what I got at least
As I don't like base-specific puzzles, I wonder. If we do the 'memorable prime' thing up to n *but* in base-n, for which values of n will hold now? Also, if we do the 'most wanted prime' thing, again, up to n, in base n, which values of n would hold now? For what values of n would hold for both the modified memorable primes *and* the modified most wanted prime?
For the most wanted prime it's interesting that not only are n%2=0 definitely not prime. but because 10%3=1, also n%3=0 will definitely be divisible by 3 as the last one was and n-2+n-1 is divisible by3. But this carries over to n%3=2 as we know that the next number is divisible by 3 and that a multiple of 3 was added.
I know Wieferich Primes has only 2 entries namely 1093 and 3511. Its apparently sequence A001220. Dont know any with only 1 currently. Fermat Primes has only 5 entires and most likely that's it.
@@nverwer 1101(2)=13(10) is prime, yes. It also works in base 3: 121021(3)=439(10) is prime; and in base 4 as well: 12310321(4)=27961(10) is prime, too. 5 is the first one where it's not prime, because 1234104321(5)=3034961(10) is divisible by 137.
This is actually in the OEIS, as sequences A260852 and A260343. So, the bases where this works are: 2, 3, 4, 6, 9, 10, 16, 40, 104, and possibly 8840 (but the last of these is only a probable prime, with 69770 decimal digits).
I'm always suspicious of messing around with functions that only work in base 10. It's not that this isn't a real problem that could be solved, it's just more than it feels like numerology instead of mathematics.
Yeah finding primes with a pattern so it's easy to remember how to write them out in base 10, not a real math problem. I guess numerology is playing with numbers like this? This play does lean on serious math problems, like for each check to decide if a candidate number is a prime, it's helpful to use a fast method for finding a number's factors (this implementation quits when it finds any, or declares prime when the search ends in failure).
If you sieve out everything divisible by 2, 3, and 5 in the search for the 1...n prime then you only need check {2k+1} intersect {3k+1} intersect {5k}' which is the numbers that end in {1, 7, 13, 19, 31, 37, 43, 49, 61, 67, 73, 79, 91, 97, 103, 109, 121, 127, ...} which is a set not on the OEIS.
My favorite thing about all of the numbers where n is less than 10, they are all square numbers. The coolest part is that the square roots of all of them are all composed of numbers made of 1s
I assume you're talking about what Neil calls "memorable primes", such as 12345678910987654321 in the first part of the vid. If we replace that '10' in the middle with 'A', a single digit equal to it by convention in number bases bigger than the usual decimal, then we do also get a square. In base eleven for example 123456789A987654321 is a square, as it is in base twelve and thirteen and so on. Even though the actual quantities that particular sequence of symbols represents differ from base to base, they're always squares as as long as we represent n with a single digit. The same applies in bases smaller than ten. On the other hand, when we represent n as 10, then we don't always get even a memorable prime, let alone a square. In base eleven, again for example, where the number after the top single digit A is 10, the number 123456789A10A987654321 isn't a prime, besides not being a square. But in the hexadecimal base, in which the top single digit is F, 123456789ABCDEF10FEDCBA987654321 is a memorable prime.
It honestly sounds like a big scam. I haven't looked into it, but: How much CO2 is released from building these machines to extract it? (How long do they need to run to offset that? Factor in maintenance as well) How much CO2 is released from running these machines? Even if they run on renewables, that amount of energy could be used somewhere else to replace fossil fuels. Unless we have 100% electricity production from renewables, this doesn't make any sense in my opinion. Storing it underground doesn't sound like a bad idea. I don't know what form they're storing it in, but it's probably basically just carbon.
genuine question: if climeworks' co2 sequestration technology takes e.g. electricity or fuel, what's the carbon footprint of that electricity or fuel? is it really a net benefit, and if so, is it enough to substantially slow climate change due to atmospheric co2?
For the 2nd part, I was wondering if this was true in other bases. I tried doing it for binary and came across a prime quite quickly, at 15 (1101110010111011110001001101010111100110111101111 = 485,098,038,695,407). I'm not sure if this means anything regarding the base 10 solution, but it does show that our arbitrary base number decision is making this more complicated than necessary!
I always find this type of sequence (that relies on a specific numeric base) kind of "meh". _Relevant_ stuff in maths is about _values_ and their properties, not about the characters you use to write them with. If the "property" you're looking for only works in base 10 but disappears in base 11 or base 8 or whatever, it's just a curiosity. It might tell you something interesting about that base (and that is especially true for base 2, which overlaps with logic / boolean algebra), but not really about the number sequence itself.
For 1...n, only n = 3m+1 (m >= 0) are possible primes. Consider n mod 3, that results in the sequence [1, 2, 0, 1, 2, 0, 1, ...]. Here, 1+2 mod 3 = 0, so the sequence of sums 1 to n is [1, 0, 0, 1, 0, 0, 1, ...].
An interesting question would be the following: when we are testing for primes, just “counting upwards”, since they have now made it to 1000000, and he said it seems statistically likely that a prime should have shown up and it hasn’t, I would think it would be an interesting idea to try and figure out WHY you can’t hit a prime counting upwards in this fashion and maybe prove it true or false. What do you guys think?
You can find primes like this in other bases though, so the chance that one doesn't exist in base 10 would be startling! If it is the case that none exists, and it can be proved that none exists, it would be interesting to know in which bases these sort of primes can or cannot be found.
A very cool topic, you could also see he really has fun with it. But there may be a problem with the video itself, around 4:50 you see some newspaper(?) covers and at least one of them is showing NSWF content which TH-cam may block, which would be sad for a fun video like this
Visit gift.climeworks.com/numberphile and us se code NUMBERPHILE10 for 10% off your purchase (sponsor)
More videos with Neil: bit.ly/Sloane_Numberphile
Prime Playlist: bit.ly/PrimePlaylist
Riemann hypothesis solutions is complex irrational number. I have one theroy 🙏. Which platform I publish my theroy plz tell me. 🙏
What happens if you reverse the order of each numbers digits after passing N? Any primes there?
I am The Crazy Scientist and I left this message here for no reason whatsoever
Does this work in other bases?
Honestly, who wouldn't want endless boxes of chocolate?
He sounds like he gets out of bed in the morning and is absolutely thrilled he gets to do more math, every single morning
High on math
This comment is delightful. :)
He is a mathematic mathADDICT
You should see Cliff Stoll talking about Topology.
4:46
Neil Sloane is always worth my time.
Whether it be odd, even or prime
He's worthy of prime time.
Neil Sloane is always prime time!
??
"Give me a prime"
"2^31 - 1"
Baller move. Brady should do that the next time Matt Parker asks for a number
I had a colleague say Graham probably knew something we wanted so I said he could call Graham's Number but it could take a while to get answered.
@@PMA65537
Graham’s number is definitely not a prime.
@@ragnkja you probably missed a joke. With 'call' the commenter meant 'making a phone call'.
A Parker Mersenne Prime? 2^67-1
@@ragnkja 2^G - 1 might be prime though!
Seeing Neil Sloane enjoy his sequences (and talk about them) is always a pleasure. Please do more interviews with him in the future!
Please do it in some other bases, I’d love to see one in base 6
He's got major Jeff Goldblum energy.
We need MOAR....! Please?
Yes, please. I'm especially here for sequences and primes.
false.
4:39 "I'm not finished. I have another segment." I don't know why, but I really enjoyed that. He loves and can talk about numbers all day.
@numberphile hey! I saw this and thought, "what about concatenating increasing values to the left" i.e. 1,21,321,4321,54321, etc.
Did a little bit of number crunching and the first one I found was at a starting value of 82.
They exist!
(I was able to speed up my search realizing that 2/3 of these are divisible by 3 and skipping testing those.)
Maybe look for the next one and make a video on it? Prime related videos are always a hit. :)
Anyway.... Loved this video! It inspired the little search I just did.
Well if these primes(assuming there will be more) don’t have a name yet, we could call them Falken primes
How far did you go? Judging by how fast the number grows there should be infinitely many (O(ln(ln(n))) below some starting value of n)
Ah, that's a nice prime.
Would that be the “least wanted prime”?
Wouldn't mind them being called Falken primes if there's no name yet.
I'm looking into other patterns that I'd be more keen to get something published for.
I didn't look past 82. Reason being I typed the number manually into an online primality test. I was more than happy finding 1. (I was willing to go up to 100)
I really need to code up something to do these things for me :)
The largest prime that I know the digits of is Belphegor's Prime:
1 0000000000000 666 0000000000000 1
Thirteen zeros before and after the number of the beast, 31 digits (13 reversed) in all.
Checkmate christians
That's so friggin cool
Of course, Numberphile has covered this number: the video "The Most Evil Number".
But are there an infinite number of primes of the form one, some number of zeros, 666, more zeros and a one? Or more than one even?
@@michaelsmith4904 the smallest prime after this one with 13 zeros is with 42 zeros (10000000000000000000000000000000000000000006660000000000000000000000000000000000000000001). also no zeros (16661) is also prime
I would love to hear more from this gentleman, he can be a narrator for some great shows
Yes. He sounds a lot like David Attenborough.
Now, Stanley was- for the first time in his life- curious as to what the next prime could be.
He uses a lot of range.
??
Prime numbers and numberphile videos about them , never get old
Great, now I can boast about knowing a 17000-digit prime by heart! Thanks
Be careful not to boast too loudly. Someone might ask you to write the number down. It could take a while.
Well, write it!
Read the Description. At the time of the video, it was only a probable prime.
@@RWBHere I really like how you future-proofed your comment.
@i liked how, at the time of reading, he had future proofed his comment.
He always seems like a child who has found something interesting to play with 😍
A Klein, interesting. You're a point of interest for Numberphile
Do you manufacture bottles by any chance?
I feel like a child who found something to play with and want to show other people my new thing!
@@avikbhattacharya6854 oh?
Yes, numbers are quite a fun thing to play with.
He better live to a hundred or I'm gonna cry
100 isn't a very interesting number - I say he should live to the age 1729
He should live for a whole number of years, to within a day.
Better to the age of N
but 121 isn't a prime number. Here n=2
@@Anonymous-df8it I think 1729 was meant to be a reference to a mathematician just like the 1729 in my username. Still agree that base-6 would've been better than base-10
I got curious and decided to try this - but with base-2 instead of base-10. And I think I found one!
01101110010111011110001001101010111100110111101111, which is 485398038695407, _is a prime_. And it contains the numbers from 0 (which might as well not be there) to 15.
I give you a virtual cookie
This comment needs more visibility!
Few others:
1 2 3 4 5 10 11 12 13 14 15(b6) is 4060073996291
1 2 3 4 5 6 10 11 12 13(b7) is 131870666077
12(b3) is 5, 12(b5) is 7, 12(b9) is 11, 12(b11) is 13, 123(b8) is 83
12345(b12) is 24677
(couldn't find anything in base 4)
Binary goes till 15 a multiple of five, 3 and 12 both go till 5. 12 and 5 together remind me alot of the golden ratio
This can actually be a big insight. Can't believe nobody bothered to look at other number systems so far!
@@CompilerHack Why does twelve remind you of the Golden Ratio? It is not a Fibonacci Number.
"It's a story you can tell at parties." I'd love to go to a party where I get to hear Neil Sloane's stories!
??
I'm intrigued by the sequences both so important and so hard to evaluate that they have the privilege to be included in the OEIS with only one entry. Tell us more about that please !
Someone else in the comments went and found all the one-term sequences on OEIS: A058445, A058446, A072288, A076337, A115453, A118329, A122036, A144134, A245206
How could something have more than one entry in the OEIS? What would that mean?
@@leif1075 They mean only one term in the sequence is known, and yet the sequence is included.
@@SSM24_ someone should make a submission made of the ids of the currently all OEIS sequences with one term
@@SSM24_ at least for A118329 the second term is known but too large to be included.
So happy to have Neil back
I love these videos with Neil Sloane. It's very soothing to hear him describe patterns.
The professor has such a beautiful voice.
I would like to note that if the step between each number is 2 instead of 1 (so 135... instead of 123...) the first prime is 13, but the first interesting one is 135791113151719
Now that's fun
Wow
Someone should run this for other steps of n
So are 1357911131517191715131197531 and 19171513119753135791113151719
@@chrisg3030 Okay that's really cool
Me: "Is this prime?"
Mathematicians: "hmm, not sure... BRING OUT THE GIMP!!!!!"
My new favorite hobby is reading all the comments on "the all 1's sequence" on the oeis.
Neil is an absolute treasure, and it’s always pure joy to watch numberphiles when he is in an episode!
by the books in his shelf it´s nice to see Professor has also an interesting in Operating Systems (Unix) and computer programming (Shell)
His areas of interest are combinatorics and error-correction which explains his bookshelf.
I am still contemplating whether this is is an ingenious and pragmatic idea of just writing the contents of the stacked books on the side of the pages or the laziness of not getting a proper bookshelf and organizing the books where you can read the actual titles.
Not to mention R.
Now I'd really like to know which sequences in the OEIS contain a single term
absolutely!
Came here to say this. You can't offhandedly mention extremely important single digit sequences and not give an example!
same!
A single term, not necessarily a single digit.
@@ragnkja _aCtUaLlY_
but yeah, you're right lol just edited the comment
I love your videos with Neil. Hands down my favorite guest on the channel!
I hope I'll have his energy at his age. Just a joy to watch.
And his voice! He is an awesome narrator, so engaged and excited.
I expect the most wanted prime number is the private key to some big bank's signing certificate, but this is maybe the coolest (to mathematicians)
It's gotta be one huge as key I tell you what
Private keys are composite.
banks do journaling once a day, so at best it'd be a big news item, but if the books don't square the transactions will not go through.
Nearly 4m subscribers, nice work. Hope you've got the special ready
Imagine being the 4 millionth subscriber lol
This is why I love numberphile !
Huh, this is interesting... I actually got 2 "most wanted primes" in hexadecimal with n < 1000, the first is 123456789ABCD (n = 13) and the other is much larger (n = 211)
Which brings up an obvious question. What if you do it in base n+1?
@@jmodified Or base n - 1, so the last amount is base + 1 so that's relatively prime to the base, too.
@@jmodified No idea... I tested up to b=256 today and n
@@caiohomar1540 Does any base have a dedicated OEIS sequence?
@@iridium141 Don't think so, I couldn't find it at least...
Curiosity and hard work and persistance are the key in any success in any field. Neil Slone has these factors and more.
His achievments in many fields are truley remarkable.
He is an Artist in my opinion.
Thank you.
can't wait to whip out this story at a party
Thank you to Numberphile for showing me the beauty of mathematics. I was in high school learning algebra when I was also watching Parker et Al and understanding little, but appreciating the beauty seen by the presenters. Thanks Brady.
As comedian Chris Ramsay said: "I don't understand what's going on, but I'm enjoying it"
@3:40 I'd love to watch a video of these 1-term sequences!
is a 1 term sequence a sequence? or is it just a scalar
@@julianatlas5172 No one knows the second term.
I was just binging all of the old Neil Sloane videos yesterday. So glad to see a new one!
I love the fact Neil has a ping pong table as a desk.
Great video.. more of Neil please.
I love Sloane's enthusiasm, it's infectious.
So is Cliff Stroll's
I always want more Sloane content!
So why did Armand Borel want a prime of 20 or more digits? What was he planning to do with the answer? We never found this out.
(BTW, is Armand related to Emile Borel of the Heine-Borel Theorem?)
Fred
In base 3, not in OEIS, for most wanted primes (or pseudoprimes), you have:
n=2 12 5d
n=5 12101112 3929d
n=82 121011122021221001011021101111121201211222002012022102112122202212221000100110021010101110121020102110221100110111021110111111121120112111221200120112021210121112121220122112222000200120022010201120122020202120222100210121022110211121122120212121222200220122022210221122122220222122221000010001 112472248900628264609109603739848048285897664360560828256938844196881901607705808202739737387845865591848483833175481611716989149644798597217d
n=2546 12...a 17096 digits base3 number and in decimals: 438901614887514605466267024386135650600033362816444496806711372482245146884915386909751348997365801080402351449028502471242758888291675821118882089624318810691875547196735723240044009073427703696943580508956388470243977950109715055427911971938769774537861003809418719662224703232659963740936759146413626780864259526623534809268264284464067573779632781576662014162616826112288023392384774287767276320175409899881761958681471740412391874176042195430070221392433210585775906449594019840671917690306383887269066440280869038221590800757726038419310165765817602141383203628163030486797195470487225017025556330003905306893745165136800294081763649102929942289549029289694486589044625755773540712708002139120512015235073943656831115285653411989128764226947221449296389459674032450987082484043225302027278826769410720791535692229493371031924259660556848144314000445654512658136867612154055336435117898846176463282467432817204323281940956831945877855475081487734707725937382588017637605467946620737185161919285910727346515604035560027325241617303161426862687582608779165975115120037965282740364477929244994948643424406776025837599317893217934242983173962854495549552925865358362160216170232431412501191185122859465062497612933449290017800399832615920842635549143644417498407282164430111190673427067279254777126182311689788339580626526879218126104793463452645047651100305200749754425281186984457004839397827526097260844873083759672695142118136400187418757225802418639267030503007125458153523931207934882184132836181235705883074168544338649964944315222818030304854865580595027150897598524505443395177578042859671886994011148667288767765497566847363098520947250508659308001673701049339493880352430223893633783346800139234340664168619262580858161177425052811238334058093109643234935631893615271178784996590633473073045834020706511677721803088305408381234753514475074849924505207886445911252646076120937379014709441628137808976455481463512462096244860345574315484717207832106753890953713937904982858926361286681194513782402190772071347397526087851818679282636863859352153479144525826571420850114077385592124609592686912007702391578702044511649340622136791579272315034250821418780278111935666966091650914548744757218825982833851583002407620557942660474959299938188913070125916269693012051653447069343388401733199482657537411375249202481112064910061966524173074310317506995281791854589825621338034046854382960671569788537973365456474490252399919779987126977112652497293767434735550597779641352914431817257830567295527502994243084492733418360365813514813082113397034621711820937265302372631858924981012233776155001023122872486769362546086022299511589199892237656094464364795419166791495343658971827297078230172672836473972499001793841210218983321833999585865141748945016812805554163352422570692230543971779497512947313915747863897248386240199933836536897429460817607741096407421334176965826575305909098151797856352021065933462319015038571632310281363782242405456561072660828085094572441184322043645967483835458792958061179945950237724064153512479640307650520223071942459696844558775725210873435662497329528062699343340547057845708465401419776666473542234739723112889506098158607358386544763603846912596365421297389929873804176039812718462615217865889168346463573509340991263267280750673373227985960761895444868329529202641984260680399880681697432376882093710003142346365239061028260990115196961790036303028664916802952870971285513130323212935759290243064700926865580807469522757708352423605709300452286552045763227345233428490525305459744051993431832215900878592453007640782228628152888142077344423394604330124218565464396362665619752655039630661092370763799913933061323982754470390704248673099689879044276844231827028973814330989322247881462852458897210262545089984831435951988634241204306544509757730686037451417570579775944158145869252098883388942146173429252051567573522530401013328583210415168947591395744568986130643890797364875606647394354008687467026202990068615725771510886684287497054500143293853741651016641308994226911706619201023960034111577893632812444224116002475647496979880940952622185932420442791808235729577171091700569556999147247238281651414307698923457125018811089030223204213471009151245308726594039942960381506400657188276351996631909496469878494341455015096590860152630086653717147052776243974920863565048770745598343350054367339632222613376129845660848073595236733729148394330150182049430153303525996965101223460297494682810714347238975208847007091915138622524610069828844642103031475682537518816620566074664714010706389507184773671166591423641463947926995682244260517480096043234676623274797478805714178010262597943473907308497240192380947608952606270183913576744271001425297221800285990491194478490872941695038781616831946021363754717166665253777716708699184844182295821946390662947508525762189741247458205462637573773038284499995562162498922657257206676548110378420888182630953507930913936162407326012853951844070139467437286092579039772558117128286112038515914839702812823662723874760982499647832179622468735509287014228638815604389024221105353488557697150202057253599945724951028100136398437626228243145428785211412623961388893948697191179006369598767232091215109668854155733795448325845458855959085896101726236478860711044573327536899308364702654108310850277643652514439466404599781514526217602434435680426173237299033136558608105430552125179732593145895855597822806797138423311127513999228141629403521076652240902990808957938670382742930185334263135596714938518686636870359196417050573013555235794819551427444692941136083169437591866053007429101593174752126422267978113947477461632199149574653056995580876468468841512503929265973642142521433783910029701927589568500637598930280799274868655321543428664359831794693822872073190107789469188420594776959536133518213026753649027479520105658505413112757606653778202698386410866669261793298774706466885673703937418813676083119806154269281559939970261119267626636028263921354951358586526357005123308387086908417130065448016969108814742360412546524023100394681035588457758593149829172706208635924807614988395060367385862447528343392322877668590782646462344060192295581656854743315229508080164680704886014611609639080074611150823795908462622284834799780945214780191321575682473098064219102968720714852110768382124024146577003342386825675534120496009149228085797296664947944284459504397362452714225723572952593450824965261345076198411518594355426018167169450570770204353854645929652792627529836025959158795973160711218806372062533011369683801669606973011385261374554712435374666368510832811165374881024432000630156605745731583527568393362099773864654120614392695816927962941961796870705942732062535883974671407701948049998941787677650275837941332147758540549249531205174662609789801130837306242411970101356781854729807193025032643207669020507166841929182848376450424724622565875933484459506081841788009168152121665356137035803619457997587710285070757557475765648197708197336087442233922801051363259058752900768683917817182530781428990233345335491142657554109362089599381648594598632774233042003995246686666171131041962498052053228777886538814004715290787801519670265151626279751436930607755928758779163379959620642739702102423695906633503666884625284074280469791454947762620400566495649335900149037140329044014471637556290564558780455387345220647032374269572508607146969505876102860307439372051463537783921506332039856547516566554110952445716883101947268480724546997982934076279121300134492266584776249333628351423955196946299312750470582678826773819518561854467008142897111691746984665531975523818102531728930681386711149231763248034500067381101184802415913930239273387662235502940626366340343163935252168633269489942804045742529029442688139410283913282798340772808136427200494607809568040254992549523782574468108842177788575245592080095055866273313609298194731956478946627062925151259845335958921788510456102392365071680602249026359659326337432520150462066773815872963830090143826783584318752589919934485486220644252851108622731473363199478507094210005490820523950776749019625467113947559352128569732955675193115243144136506697105041288337632419988844340393521444498029143167750726032348124797660335107
Woah.
You know Borel was a mathmatician and not a computer scientist because he couldn't quickly calculate 2^31-1 in his head :p
😂😂
I can't bear the sound of that sharpie pen writing on that rough paper!
Brady: Should we believe there are an infinite numbers of n's this will work for?
Neil: Yes, do the math.
Me: I don't think I will.
I don't think I can
@@GodwynDi Nobody can, yet.
@@GodwynDi If you have any sort of stem degree, then you probably know (or knew at one time) enough math to do it. I assume you would: look up "distribution of primes", find an approximate distribution of these numbers with a simple form - which looks easy, then determine if the sum of expected number of these primes computed from those results diverges - which could be difficult but is probably very easy. That is assuming of course that there is nothing "special" about these numbers in relation to primes, which seems very unlikely given the form of the numbers.
@@jmodified I probably could have when I graduated college, but that was near 20 years ago. And I don't use any complex math anymore. Still enjoy following the stuff though.
Well, the number of primes like this will be an extremely small subset of all integers. But, since there are an infinite number of integers, any subset with members that occur periodically would, by definition, also be infinite.
This is an absolute gem. Thank you.
God I hope you have 100 Neil Sloane videos backlogged. This man is my math grandfather. What a treasure.
Yes the legend is back
2:40 Ten works! And 2,446! And beyond that we don't know... But we DO know there are an infinite number of them! And THAT's why I love Numberphile so much!
Well, to be fair, we don't KNOW that there are any more, we're just assuming that because it's a completely artificially constructed number so it's equivalent to picking at random (taking into account things like the numbers not being even etc) and we can calculate the probability of a number in a certain range being prime so we can calculate the average amount of primes in the first n numbers of the sequence and it diverges therefore one could say it's probably infinite
Why does this wrong comment get so many upvotes? We don't know, man!
@@Rank-Amateur no it doesn’t. For N= 1 you get the number 1, which is not a prime.
@@gregoryfenn1462 1 is divisible only by itself and 1, checkmate
@@SlenderSmurf OK, but 1 is still not a prime number
4:49 -- nice magazines you have on the wall there, old man !! :D
.
I liked Neil's little moment of flailing, frustrated at being unable to find any primes.
Get me pictures of spiderman!
Your enthusiasm is SO contagious. 😁
Very base-10 heavy. The number 12345678910987654321 is indeed very memorable, and a nice piece of trivia at a party, but it seems like nothing particularly special because the fact that we write in base 10 is so arbitrary. I'd be curious to know if we wrote in base-12, for example, or base-n, whether either palindromic sequences or sequences that stop at n would be prime.
I feel the same way about 3301 and 1033 both being prime. Neat fact, but not very meaningful. People easily conflate the properties of the *representation* of a number, with the number itself (I think partially because people aren't taught much about other notations in school, especially other bases.).
This is related to recreational mathematics. You don't seek for beneficial in math at all, problem is problem. The number is in base 10 but It is not true that these problems are not important mathematically.There are serious problems in recreational math and the way to solve them sometimes lead to important areas.
This is gold. A true TH-cam treasure.
Neil: I encourage everyone to continue the search and find that smallest value of n which is prime.
Me: Or prove such an n doesn't exist?
Its possible there an infinate many, just very rare. First counter example could be say n = Gogulplex (well heristically) and occur with probability 1/log_gogulplex n
We'd never find one of that were the case
Or prove that this puzzle is unsolvable (i.e. you can't prove it doesn't exist yet you can't find a smallest value that's prime)!
@@Anonymous-df8it You can't prove that this puzzle is unsolvable, because if there is such a prime, then once you know the example, it's trivial to prove that the puzzle is solvable, therefore, your "proof" that the puzzle is unsolvable proved that there is no such prime, which solves the puzzle and contradicts itself.
I guess Neil already knows that they exist, otherwise they would've mentioned that it hasn't been proved.
Spent some time working out a formula for the amount of digits of the number resulting from writing 1 up to n and back down to 1 written in base b.
d(2*n+1)-(2/(b-1))(b^d-1)
where d = floor(log_b(n))+1 or in other words the amount of digits of n when written in base b
A petition to authorise 1 to be a prime number would solve this problem easily!
and break mathematics ;)
And then mathematicians would look for the 2nd smallest such number and we're stuck again.
“Bring out the Gimp”
“But the Gimp’s sleeping”
“Well, you’ll just have go wake him up now won’t you?”
he sounds like he's very well practiced at saying "sorry"
at 3:15 I was just looking at the large number and i noticed one of the lines (starting with 646645) ends with ... 276 266 256 (next line): ... 246 236 226 216 ... and more increments of 10.
Isn't it cool that with three digits going one step downwards on each number if you look at it moved by one it goes down by 10? just a random musing, don't mind me haha
Yeaah, Neil Sloane the Legend
To speed things up you can assume the number Must not be Even Or end in 5, It must also not end in any N=3(x) as (N-2)+(N-1)+N Where N is a Multiple of 3 Is Also A Multiple of 3 (as 3n-3 is a multiple of 3 For all whole solutions). This Eliminates quite a lot of numbers
What does the most want problem look like in other bases?
Partial answer for base 2 n=15 (1111) Is prime (1101110010111011110001001101010111100110111101111) (485398038695407)
Is there a prime of the sort 1357911...? Or how about you do consecutive digits like before but needn’t start at 1? How does the story change then? 😊❤
I really hope this video helps find the first prime like that.
me too!
me three!
Me 2^2
Me 2^2 + 1 (the 2nd weirdest prime number)
Neil is a joy to listen to
Time for a part 2 where Matt Parker writes some python code and almost finds one which we can call a Parker prime
😂
Remember rectangles are “Parker squares”.
I think I found a “Parker Prime” for you! If you write the numbers from 1 to 121 side by side and treat it as a long decimal number [which would likely too big to visualize in the observable universe] then that number's smallest prime factor is 278,240,783 [more than 80% of the American population].
Enjoy! :)
Neil is great and he is obsessed with prime numbers. Please show more of his videos.
I wonder if the 1 .. 10 .. 1 prime works for every base you write the number in (like stopping when you reach the base). It seems to work for base 2 and 3
It worked for 4 but failed on 5, from my test. I might have messed up and it was a quick n dirty test and some of my tools might be bad, but thats what I got at least
I tried 16 too and it works
@@sock7896 Is 5 the *only* counterexample?
As I don't like base-specific puzzles, I wonder. If we do the 'memorable prime' thing up to n *but* in base-n, for which values of n will hold now? Also, if we do the 'most wanted prime' thing, again, up to n, in base n, which values of n would hold now? For what values of n would hold for both the modified memorable primes *and* the modified most wanted prime?
For the most wanted prime it's interesting that not only are n%2=0 definitely not prime. but because 10%3=1, also n%3=0 will definitely be divisible by 3 as the last one was and n-2+n-1 is divisible by3. But this carries over to n%3=2 as we know that the next number is divisible by 3 and that a multiple of 3 was added.
The same is true for n%11=0 and n%11=11-1. And the pattern holds for 111, 1111,...
Found out this wasn't true but the 3 one still is
As always, captivating, educational and entertaining. 😊👍
3:32 Any examples of those one-term sequences?
I know Wieferich Primes has only 2 entries namely 1093 and 3511. Its apparently sequence A001220. Dont know any with only 1 currently.
Fermat Primes has only 5 entires and most likely that's it.
Cool that he gets to work in a Whataburger themed office.
I'm curious about other bases. Is it just a coincidence that the first one works for n=10 in base 10?
It works for base 2.
@@nverwer 1101(2)=13(10) is prime, yes. It also works in base 3: 121021(3)=439(10) is prime; and in base 4 as well: 12310321(4)=27961(10) is prime, too. 5 is the first one where it's not prime, because 1234104321(5)=3034961(10) is divisible by 137.
This is actually in the OEIS, as sequences A260852 and A260343. So, the bases where this works are: 2, 3, 4, 6, 9, 10, 16, 40, 104, and possibly 8840 (but the last of these is only a probable prime, with 69770 decimal digits).
@@renerpho Huh, no one checked it yet? 70k digits should be barely solvable by supercomputers I think
@@viliml2763 There are a lot of 70k digit numbers. It seems like indeed no one got around to check this one yet.
The way he enounciates question is oddly soothing
I'm always suspicious of messing around with functions that only work in base 10. It's not that this isn't a real problem that could be solved, it's just more than it feels like numerology instead of mathematics.
Yeah finding primes with a pattern so it's easy to remember how to write them out in base 10, not a real math problem. I guess numerology is playing with numbers like this?
This play does lean on serious math problems, like for each check to decide if a candidate number is a prime, it's helpful to use a fast method for finding a number's factors (this implementation quits when it finds any, or declares prime when the search ends in failure).
Conway's 'Look and Say sequence" is even more arbitrary, and yet it proved to lead to some interesting mathematical developments.
i wonder if you take the first n digits of something like pi or e and find for what n that number is prime
N has a lot to answer for in mathematics. There is a huge weight on it's shoulders.
If you sieve out everything divisible by 2, 3, and 5 in the search for the 1...n prime then you only need check {2k+1} intersect {3k+1} intersect {5k}' which is the numbers that end in {1, 7, 13, 19, 31, 37, 43, 49, 61, 67, 73, 79, 91, 97, 103, 109, 121, 127, ...} which is a set not on the OEIS.
Maybe it’s just his genuine enthusiasm for the subject he’s discussing, but Neil reminds me a lot of Richard Feynman in his mannerisms and speech.
Every video of numberphile is so informative and enjoying, surely a boon for math lovers.
My favorite thing about all of the numbers where n is less than 10, they are all square numbers. The coolest part is that the square roots of all of them are all composed of numbers made of 1s
I assume you're talking about what Neil calls "memorable primes", such as 12345678910987654321 in the first part of the vid.
If we replace that '10' in the middle with 'A', a single digit equal to it by convention in number bases bigger than the usual decimal, then we do also get a square. In base eleven for example 123456789A987654321 is a square, as it is in base twelve and thirteen and so on. Even though the actual quantities that particular sequence of symbols represents differ from base to base, they're always squares as as long as we represent n with a single digit. The same applies in bases smaller than ten.
On the other hand, when we represent n as 10, then we don't always get even a memorable prime, let alone a square. In base eleven, again for example, where the number after the top single digit A is 10, the number 123456789A10A987654321 isn't a prime, besides not being a square. But in the hexadecimal base, in which the top single digit is F, 123456789ABCDEF10FEDCBA987654321 is a memorable prime.
@@chrisg3030 that's cool and flys over my head a bit, but I'm just taking base ten.
Wonderful!
I wonder if it is the "prime" accused in a crime?
Hello
3:02 - Seems guaranteed to get you invited back.
This is now the largest prime that i can keep in my head and write down :D
after this i feel an immense need to go find that prime
This climeworks actually sounds like setting up a timebomb for future generations.
Let's store it all underground, "fill" the "land" if you will. Nothing could possibly go wrong.
It honestly sounds like a big scam. I haven't looked into it, but:
How much CO2 is released from building these machines to extract it? (How long do they need to run to offset that? Factor in maintenance as well)
How much CO2 is released from running these machines? Even if they run on renewables, that amount of energy could be used somewhere else to replace fossil fuels.
Unless we have 100% electricity production from renewables, this doesn't make any sense in my opinion.
Storing it underground doesn't sound like a bad idea. I don't know what form they're storing it in, but it's probably basically just carbon.
genuine question: if climeworks' co2 sequestration technology takes e.g. electricity or fuel, what's the carbon footprint of that electricity or fuel? is it really a net benefit, and if so, is it enough to substantially slow climate change due to atmospheric co2?
That's a big reason why it's in iceland - power there is largely geothermal, which is as close to zero CO2 outputting as you can really get.
@@avoisin that makes a lot of sense. i'll look into supporting them, then.
For the 2nd part, I was wondering if this was true in other bases. I tried doing it for binary and came across a prime quite quickly, at 15 (1101110010111011110001001101010111100110111101111 = 485,098,038,695,407).
I'm not sure if this means anything regarding the base 10 solution, but it does show that our arbitrary base number decision is making this more complicated than necessary!
In base 3, the first prime is actually 12 (=5)!
Well, we can conjrcture that such prime numbers exist regardless of the base, but how we can prove this?
So there could be one of the form 1234567891011...9999979999989999991000000 etc
Not nearly enough discussion is made about repunits (all 1's) as candidate primes. Worthy of more exploration!
I always find this type of sequence (that relies on a specific numeric base) kind of "meh". _Relevant_ stuff in maths is about _values_ and their properties, not about the characters you use to write them with. If the "property" you're looking for only works in base 10 but disappears in base 11 or base 8 or whatever, it's just a curiosity. It might tell you something interesting about that base (and that is especially true for base 2, which overlaps with logic / boolean algebra), but not really about the number sequence itself.
I definitely agree. But having said that, it's pretty cool to know by heart the decimal digits of a prime number that is thousands of digits long...
For 1...n, only n = 3m+1 (m >= 0) are possible primes. Consider n mod 3, that results in the sequence [1, 2, 0, 1, 2, 0, 1, ...]. Here, 1+2 mod 3 = 0, so the sequence of sums 1 to n is [1, 0, 0, 1, 0, 0, 1, ...].
An interesting question would be the following: when we are testing for primes, just “counting upwards”, since they have now made it to 1000000, and he said it seems statistically likely that a prime should have shown up and it hasn’t, I would think it would be an interesting idea to try and figure out WHY you can’t hit a prime counting upwards in this fashion and maybe prove it true or false. What do you guys think?
My thought exactly are we sure that there actually exist a n such that the number becomes prime.
You can find primes like this in other bases though, so the chance that one doesn't exist in base 10 would be startling! If it is the case that none exists, and it can be proved that none exists, it would be interesting to know in which bases these sort of primes can or cannot be found.
@@LunizIsGlacey Someone gave it a shot in various bases and bases 4, 13, 18, and 19 also don't have small primes of this form.
@@coopergates9680 May I ask where you got this info?
@@iridium141 Did it work when I tried to tag you in the thread where someone offered that info?
A very cool topic, you could also see he really has fun with it. But there may be a problem with the video itself, around 4:50 you see some newspaper(?) covers and at least one of them is showing NSWF content which TH-cam may block, which would be sad for a fun video like this
GIMP is a graphics program. GIMPS is looking for primes.
I love the way he says, “Sorry!”
I suggest another challenge: Try looking for this last kind of prime where the base=n.
Ah, I just suggested that above, using n + 1 though - otherwise you've gone one past the clean part.
I realized at the end that I had been smiling throughout the video