%I #10 Sep 08 2022 08:44:53
%S 2,17,19,23,31,37,43,47,59,61,79,83,101,107,109,127,137,149,157,167,
%T 173,179,181,191,193,197,211,223,227,257,263,269,271,281,307,313,317,
%U 347,383,401,421,433,443,449,457
%N Primes p such that 91 is not a square mod p.
%H Vincenzo Librandi, <a href="/A038980/b038980.txt">Table of n, a(n) for n = 1..1000</a>
%t Select[Prime[Range[120]], JacobiSymbol[91, #]==-1 &] (* _Vincenzo Librandi_, Sep 10 2012 *)
%o (Magma) [2] cat [p: p in PrimesUpTo(457) | not IsSquare(R! 91) where R:= ResidueClassRing(p)]; // _Vincenzo Librandi_, Sep 10 2012
%K nonn,easy
%O 1,1
%A _N. J. A. Sloane_.
%E Offset changed from 0 to 1 by _Vincenzo Librandi_, Sep 10 2012