Skip to main content

All Questions

Filter by
Sorted by
Tagged with
9 votes
3 answers
2k views

May $p^3$ divide $(a+b)^p-a^p-b^p$?

Do there exist positive integers $a,b$ and a prime $p>\max(a,b)$ such that $p^3$ divides $(a+b)^p-a^p-b^p$? The reader of Kvant magazine A. T. Kurgansky asked to prove that such $a,b,p$ do not ...
Fedor Petrov's user avatar
5 votes
1 answer
354 views

Gadgets as primality tests

From the literature, showed below, I know two gadgets that provide a way to know if a positive integer (a positive quantity of units) is composite or a prime number. I would like to know if in the ...
user142929's user avatar
3 votes
1 answer
163 views

Increasing sequences and Wieferich primes

We are trying to show that primes of the form $a(n)$ can't be Wieferich primes. For natural $n$ define $J(n)=(2^{n-1}-1) \bmod n^2$ and if $n$ is power of two define $J(2^n)=1$ (this is artificial, ...
joro's user avatar
  • 25.4k
1 vote
0 answers
376 views

Astonishing affinity of Wolfram's rule 110 to the numbers 2 and 7

I investigated the evolution of a single black cell on 1-dimensional grids with periodic boundary conditions of variable sizes $N$ under Wolfram's rule 110 which is the only one for which Turing ...
Hans-Peter Stricker's user avatar