cp's OEIS Frontend

A096640 Smallest prime p == 7 mod 8 (A007521) and p > prime(n+2) such that p is a quadratic residue mod the first n odd primes 3, 5, 7, 11, ..., prime(n+1), and p is a quadratic non-residue mod prime(n+2).

%I A096640 #10 Mar 07 2013 17:12:55
%S A096640 23,7,31,79,631,751,2311,21319,48799,82471,256279,78439,1768831,
%T A096640 1365079,2631511,1427911,4355311,5715319,49196359,117678031,180628639,
%U A096640 475477759,452980999
%N A096640 Smallest prime p == 7 mod 8 (A007521) and p > prime(n+2) such that p is a quadratic residue mod the first n odd primes 3, 5, 7, 11, ..., prime(n+1), and p is a quadratic non-residue mod prime(n+2).
%C A096640 Same as smallest prime p == 7 mod 8 with the property that the Legendre symbol (p|q) = 1 for the first n odd primes q = prime(k+1), k = 1, 2, ..., n, and (p|q) = -1 for q = prime(n+2).
%t A096640 f[n_] := Block[{k = 2}, While[ JacobiSymbol[n, Prime[k]] == 1, k++ ]; Prime[k]]; t = Table[0, {50}]; Do[p = Prime[n]; If[Mod[p, 8] == 7, a = f[p]; If[ t[[ PrimePi[a]]] == 0, t[[ PrimePi[a]]] = p; Print[ PrimePi[a], " = ", p]]], {n, 10^9}]; t
%Y A096640 Cf. A096635, A096636.
%K A096640 nonn
%O A096640 0,1
%A A096640 _Robert G. Wilson v_, Jun 24 2004
%E A096640 Better name from _Jonathan Sondow_, Mar 07 2013