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%I #8 Sep 09 2012 11:09:25
%S 5,11,13,17,23,31,37,47,67,79,83,97,101,103,109,127,131,137,149,151,
%T 181,191,193,197,211,223,233,239,241,251,263,307,311,331,337,347,353,
%U 359,373,379,389,409,419,421,433
%N Primes p such that 57 is not a square mod p.
%H Vincenzo Librandi, <a href="/A038936/b038936.txt">Table of n, a(n) for n = 1..1000</a>
%t Select[Prime@Range[120], JacobiSymbol[57, #] == -1 &] (* _Vincenzo Librandi_, Sep 09 2012 *)
%o (PARI) select(n->!issquare(Mod(57,n)),primes(100)) \\ _Charles R Greathouse IV_, Sep 09 2012
%K nonn
%O 1,1
%A _N. J. A. Sloane_.