# 78557 and Proth Primes - Numberphile

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**Published on Nov 13, 2017**- James Grime is back and talking prime numbers.

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More on prime numbers: bit.ly/primevids

James Grime: singingbanana.com

Editing by Pete McPartlan

Music by Alan Stewart

Read about Sierpinski Numbers: en.wikipedia.org/wiki/Sierpinski_number

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Cheeseburger Monkey6 days ago19 x 2^1 + 1 = ~50% of 19 x 2^2 + 1

Vaughn Tiffany8 days agoah, yes, the most important thing. truthiness.

Venkatesh babu11 days agoThere are two fields electric and magnetic which spin orthogonally with lines of masses created out of this fields. Some primes create matter and others anti matter. Usually smaller and smaller primes interaction are dark matter. Interaction between smaller and larger primes are just ripples and energy transfer and expansion and spins. The interaction between larger primes are matter sun and stars and galaxies. Larger twin primes are always stars. Interaction of larger distant primes are always atoms and elements and chemical reactions. Galaxies are extremely large twin primes.

MalcolmCooks2 months agoI program my home computer, beam myself into the future

Hamster 54542 months agoJames is the best guy on numberphile

Or matt

Mykala Hawkins3 months agoYou have a new sub.

Lau Bjerno3 months ago"Truthiness"?? Never heard that word before. It sounds like someone trying to sell a lie.

Lego Mini Movies RJG3 months agoYou came to my school today yay!

Lux Ferre3 months agoJames Prime is back!

Strathaird3 months agoWow... Unbeleivable!

FGV Cosmic4 months agoIdiots.... K=0....

K*2^n+1 always=1...

1 is not a prime..........

Arian.behbahani4 months agowhy does this guy look like the Walmart Yoddel kid

Gegi Zambakhidze4 months agoPrime numbers are so weird. It's one of the things that humanity still hasn't found general formula of.

Jesse Bailey4 months agoWhat if my K is equal to 0 ;)

flomeister ShadoWmAsTeR5 months agohow did the addition function appear?

Ink Sans5 months agoI was think it could be 301 views

nDante Live5 months agoWhy don't try a proof like the number 78557? Thx

Kshitij Arora5 months agoCan you plss put up a video for integral((√sinx)dx)

Caesar C.5 months agoHow many possible combinations of notes are on an 88 keys piano ? As in a chord

Chris Byers5 months agoSooo... your sexually attracted to numbers?!?

Ricky's Beets5 months agowait are they called proth primes or colbert primes?

David Britt5 months agoAny chance we can get a James Grime video on Gaussian primes? There has to be something cool to see when you put together primes and the complex plane.

James Cooper5 months agoOff topic but could you please explain why, 2,3,7&8 don't exist in perfect squares???. & is there a proof they don't?

mahdi mcheik6 months agobig fan :) can you please explain the FFT reordering trick and how it works

satish kumar Ranjan6 months agoplease make video on approximation techniques for tough number... please

James Bateman6 months agoHey in my math class we got a problem where you had to find the area of a shaded area in a triangle. It is Geometry so it's fairly simple and the area of the Shaded triangle is also a trapezoid if you solve it by finding the area of the whole triangle and subtracting the area of the smaller triangle on top it comes out with a different answer than if you just find the area the trapezoid our teacher can't figure out why and I was wondering if I sent this to you you guys could explain why this was the way it was

Дрозд Анатолий6 months ago111 111 111 kare = 1.2345679 × 10^(16), menm jan li pral gade san yo pa yon kalkilatris?

Anastasios Chronopoulos6 months agoUhh... 0 works as a Sierpiński number

Fusion Tricycle6 months agoTry k=1

The Peanut Butter Crew RBLX6 months agoi wish i learned this in 5th grade

slinkytreekreeper6 months agoWhy is this important to know the largest primes with scores and scores of numbers?

abhay prakash singh6 months agoRequest or suggestion: Hi...please do something on AVERAGE SPEEDS, like where we can replace (two different) speed(s) by average speed etc...like 'Every day a person walks at a constant speed, V1 for 30 minutes. On a particular day, after walking for 10 minutes at V1, he rested for 5 minutes. He finished the remaining distance of his regular walk at a constant speed, V2, in another 30 minutes. On that day, find the ratio of V2 and his average speed (i.e., total distance covered /total time taken including resting time)'.....and guess what, it is 1:1. Plz do something like this please.

Rajiv Pokharel6 months ago"12345679" is quite a special number too.....

Drag0nEYE 15106 months agoIt looks like he's drawing on a trailer house curtain.

Herrgolani6 months agoI have a question concerning their testing method. You can test if one of these numbers is a prime, but not if it isn't. I mean at what power to you say "Ok, this is probably isn't a prime"? Even then, it doesn't prove that they do not have a prime number. Perhaps its just taken to a power higher than what was previously tested. I'd love to hear an answer! :)

Leo1796 months agocould you do the first 78557 people get 78.557% off?

Doubtful Guest7 months agoI'm never going to use this maths.

driven7897 months agowho care about Proth Primes?!?

mienzillaz7 months agoSo where is that glory for Hungarian..? I don't know his name.. some guy.. pfff

gluino7 months agoJames Grime is my favorite in Numberphile.

tomvondeek7 months agoHuh i haven't seen a video about Pi for a long time... here is a question i asked myself, but i'm not mathematician enough to answer it myself:

if you add / substract / add / substract etc. all digits of pi... what whill happen?

e.g. 3.14159265359... = 3-1+4-1+5-9+2-6+5-3+5-9... right now its -5. But in theory... would it be possible to go up to infinty? or to negative infinity? after all, would it converge to 0, because after all, digits are kind of equally distributet? is there any way to get any sort of answer? may some fellow mathematician try to answer? ^^

voornaam achternaam217 months agobut what if one of these five IS the smallest one?, if we only stripe them away, and there is one, we will never find it...

Lanetwin7 months ago@numberphile solve the dang cube already😂😂

I dont do birthdays7 months agoDoes Steven Colbert know there are prime numbers named after him?

Kevin Zimmerman7 months agoIs James Grime single?

A Random TASer7 months agoTwo plus two is four minus one that three quick maths

PradeepKumar Rajendran7 months agoI'll grateful if any of the regular subscribers could answer my irrelevant question. I am looking for a video that I watched more than a year ago or so, with Dr. James Grime talking about possible outcomes/predicting outcomes. I vaguely remember that he also simulated all the possible outcomes that was making a pattern and he ends up with a philosophical view "...if freewill exist?". I'm not sure those outcomes were inside the mandelbrot set.

Strikes bell to anyone? I'm desperately looking for that video. Thank you!

Gujarati Sayari7 months ago^{+1}/* Do not display this comment */

Joe Q8 months ago"We don't know it's true. It just feels true - in our guts; it has truthiness." Yes. It smells like truth. No need for further research. Truthiness is truth everyone.

Susan Amber Bruce8 months agoCan a number be expressed as being pregnant?

e. g. 1 + 1 = 2, how can 1 be expressed as being added to before it's value changes?

Promit Chakrabarty8 months agoGreat video as always. BTW, I can't figure out this problem. Finally posting this on a mathematically inclined group as no one on the Internet seems to be willing to answer this. Actually I'm appearing for an important test and it would be very helpful for me to know some facts. Based on current performance analysis on mock tests, my guesses are likely to be correct 50 percent of the times(ie, 50 percent chance of getting an Mcq correct or 50 percent accuracy) in a 4 option multiple choice question exam (mcq type exam) of total 300 questions, with 4 marks awarded for a correct answer and 1 mark deducted for every wrong answer. This 50 percent accuracy is for the 1st 250 questions I attempt which I tend to get right in the above mentioned percentage. For the next 50 however, upon guessing I would be right no more than a random chance of 25 percent. Then what is the optimum number of questions I should attempt to get the maximum marks, while getting the minimum negative marks? And what would that value be for a range of 40 to 60 percent accuracy for the first 250 questions ? I apologise if my question seems too complicated, as I myself am flummoxed by it. Would it be best to answer all, as the marking scheme seems to favour guessing? Thanks in advance for indulging in the cerebral effort.

Donțu Daniel Nicolae8 months agoCool fact: sqrt(256-31)=15 and sqrt(256)-31=-15

Tinta Dunia Maya8 months agopleaseee. use whiteboard instead of papers. :'(

Abhishek Kumar8 months ago314 people. Why, that's PI!

Oleg Shelemetev8 months agoI am poor.

Plz give me bitcoin

1CXWehPKnWZMHpxcD9YU8RfoTuHAeXr5GC

Jack Rycroft8 months ago0:13 WHAT IF I SAY IM NOT LIKE THE OTHERS

*coughs*

Sorry

Periner F8 months agoЧто за кортонка???? Купи уже себе тетрадь!!

GregoryTheGr8ster8 months agoPrime numbers are so pure.

Rmac5248 months ago^{+1}Have people tried to prove that some of the candidates are in fact Sierpinski Numbers?

A R V C8 months ago^{+1}I have a challenge for you:

I call it the Kalen challenge (don’t ask about the name).

You have to find a number that is divisible by a formula formed by numbers from 0 to 100 or just the number (include the zero!).

For example:

9900 divided by 100= 99

9900 divided by 99=100

9900 divided by 3x3||3=100

For the ecuations, you can use: addition, subtraction, multiplication, division, brackets, powers (they have to be of the same number), roots (the same number, so I don’t see much utility), concatenation, factorials (the ! thing) and points of the same number (12.12).

You’re also not allowed to do formulas that always give the same result, like (n+n) divided n, which always equal 2, and you’re not allowed to use the number 0 as the answer to the challenge, since that number can be divided by every other number.

A tip is for the last two digits to be 00, which immediately makes it divisible by 100, 10, 5, 4 and 2.

Have fun!

Iván Rangel8 months agoIt has "truthiness" - I guess James is a fan of Colbert too

Marinela Oana8 months agoWho is watching this yesterday?

JetPackJan8 months agowhat about 19 * 2^0 ?

Agustin Caputo8 months agoplease watch this videos at 0.5 x speed, is hilarious

Paradox8 months agowould $99.00 be called Amazon Prime?

Leo Liu8 months agohow do they eliminate a number if they have to check all the values of N till infinity?

Joseph Sabo8 months agoMaths is everywhere you go. Snow widows homes plants eta.

Плесень и Липовый Мёд8 months ago^{+1}Союз нерушимый республик свободных

Сплотила навеки великая Русь,

Да здравствует созданный волей народов

Великий, могучий Советский Союз

Big Beige Bastard8 months agothe first pi people

Dr Ivo Robotnik8 months ago82 people with Dyscalculia disliked this video

misterjohn john8 months ago;~)

hhh hbk8 months ago1=2

2=4

3=16

4=65536

5=?

Hussein Badawi8 months agoHi Brady,

I really appreciate your ongoing hard work and wish you all the best.I have one question which I kindly request you to pass it to Dr. Grime which is: “what is the limit of x^2+x as x goes to infinity”?

Many thanks in advance.

Hussein

pneumonosaur8 months agoPlease sirs and madams, I would like to know more about the number 72. Of all of the numbers should not this one top the charts as being oddly important!!

Frídi Atlason8 months ago2 + 2 = 4

4 - 1 = 3

Quick maths

Artemirr Lazaris8 months agoWhy not the significance of primes in music intervals, and how changing the hertz in its relation within primes can find other iterations of harmony, of course not every marriage is complete, within this thought, there would be stepping stones between, but basing the freq. in bases of differing primes rather than just the fifths, allows for a broader depth of musical scoring. Which would be .. something interesting... but I suppose in some regard that is done, by other means, but not to scale... Hmmm Thoughts..

zombiebro98 months ago474 is a lychal number

Chris Pi8 months agoNo one reacts about the Rubik's cube stuck in the armrest ?

Trivendram pal8 months agosir I have a question and please answer it ,,sir as we seen that (1+2+3+4........)=-1/12 gives a negative number then does it will also true for if we add negative numbers and will get apositive number as (-1-2-3-4-5-6........)=1/12 by using the math as. ...-(1+2+3....)=1/12... sir by these results what we can conclude ,,,,our mathematical calculation is wrong ,,,or maths is giving a wrong answer ,,,,,but math cannot give a wrong answer if we have performed it as we do usual then what is the reason behind this we are getting such a absurd result ,,,, doex these results are challinging us that we are wrong

DNVIC8 months ago0*anything=0

0*2^n+1=1

1 isn't prime

there you go

Emily Nep9 months agolol e

gedstrom9 months agoIs there a special shortcut test for Proth primes? I know that the reason that most of the largest primes are Mersenne primes is because there is a special test for them.

ahasd9 months agoyou've got funny pronunciation of "Sierpiński"

anyway, nice video :P

jack lloyd9 months agoI had the privilege of seeing James talk about codebreaking at Salford University last Thursday

Corrodias9 months agoBut how was it proven that the one number there never produces a prime?

Olivier L. Applin9 months agoI just learned about the Catalan number in discrete math class and this thing is AMAZING ! It describes so many different problems. I know it is not related to primes, but I'd love to watch Dr Grimes or Matt Parker (or anyone else as a matter of fact) explaining it!

Myles F9 months agoSo Mersenne Primes are Proth Primes such that k = 1.

mrdabbleswithpotion9 months agoDumbass. Stick with following the math problems with those "fun math books" meant to entertain the public of the wonders of math. OK, you can also find those things easily on the internet now.

정제윤9 months agoIsn't every prime a Proth prime(except 2 if you don't want 0 on the exponent)? Cause every prime is odd and odd numbers are 2n+1. In the case of 2, 1×2^0+1=2

Kelvin Kersey9 months agois there anything special about 151 136 and 287? (apart from adding the first two :-)

sammbo2509 months agoAre they just running through tons of number using 'computation' or proving it mathematically. I would hope that advanced mathematicians would prove it.

Why So Tense?9 months ago^{+2}does this mean 3 is a proth prime?

1 x 2 + 1

Mulijadi Tee3 months agoLost Realms no

warspyking9 months agoA video on the proof of why (the number we currently believe is the smallest that never produce a prime) we know will never produce a prime would be nice.

Jack Ladell9 months agoHow do you know that 78557 is? If you know that one is by proof cant you apply that method to the other 5? Wouldnt that be faster. Or im i missing something?

Jonathan Holden9 months agoFor a quick check, the digits of 153 can be added (1+5+3=9) and the result is divisible by 3, meaning that 153 itself is divisible by 3.

GENIUS9 months agoHere's a fun little exercise:Prove that 78557 will never produce a prime when taken in the form :78557*2^n+1

Hedning13909 months agoWhy did 78557 have a proof, but the others have to be done by counterexample?

Edit: ok, they didn't prove it. I should probably watch the whole video first...

rlt1529 months agoTruthiness- I don't think I have ever heard that term on here before :)

msolec20009 months agoIt's always nice seeing Dr. James Prime doing his thing.

Georticon YT9 months agoThere is always a Rubik's cube in the background...