A121999 Primes p such that p^2 divides Sierpinski number A014566((p-1)/2).

29, 37, 3373

Offset: 1

Author

Alexander Adamchuk, Sep 11 2006

Keywords

• bref
• more
• nonn

Comments

Subsequence of A003628.

No other terms below 10^11. - Max Alekseyev, Sep 18 2010

Links

• Eric Weisstein's World of Mathematics, Sierpinski Number of the First Kind.

Crossrefs

Cf. A014566, A003628.

Programs

Mathematica

Do[p=Prime[n];f=((p-1)/2)^((p-1)/2)+1;If[IntegerQ[f/p^2],Print[p]],{n,1,3373}]

PARI

{ forprime(p=3, 10^11, if(Mod((p-1)/2, p^2)^((p-1)/2)==-1, print(p); )) } \\ Max Alekseyev, Sep 18 2010

Formula

Elements of A125854 that are congruent to 5 or 7 modulo 8, i.e., primes p such that p == 5 or 7 (mod 8) and 2^(p-1) == 1+p (mod p^2). - Max Alekseyev, Sep 18 2010