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 A121999 Primes p such that p^2 divides Sierpinski number A014566((p-1)/2). 6
 29, 37, 3373 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 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. 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 MATHEMATICA Do[p=Prime[n]; f=((p-1)/2)^((p-1)/2)+1; If[IntegerQ[f/p^2], Print[p]], {n, 1, 3373}] PROG (PARI) { forprime(p=3, 10^11, if(Mod((p-1)/2, p^2)^((p-1)/2)==-1, print(p); )) } \\ Max Alekseyev, Sep 18 2010 CROSSREFS Cf. A014566, A003628. Sequence in context: A167470 A152865 A108272 * A069530 A259032 A087144 Adjacent sequences:  A121996 A121997 A121998 * A122000 A122001 A122002 KEYWORD bref,more,nonn AUTHOR Alexander Adamchuk, Sep 11 2006 STATUS approved

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Last modified November 21 05:14 EST 2018. Contains 317428 sequences. (Running on oeis4.)