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%I #15 Jun 24 2019 00:43:25
%S 3,5,17,19,31,59,61,67,71,73,79,101,103,107,127,137,149,151,157,167,
%T 179,197,211,223,227,229,233,277,307,313,331,349,353,379,383,389,397,
%U 431,439,457,461,487,523,541,547
%N Odd primes p such that 19 is a square mod p.
%C Also, only entries p=1 (mod 4) of the sequence are squares mod 19 (from the quadratic reciprocity law). - _Lekraj Beedassy_, Jul 21 2004
%H Vincenzo Librandi, <a href="/A038891/b038891.txt">Table of n, a(n) for n = 1..1000</a>
%t Select[Prime[Range[100]], JacobiSymbol[19, #] != -1 &] (* _Vincenzo Librandi_, Sep 07 2012 *)
%o (PARI) isok(p) = (p>2) && isprime(p) && issquare(Mod(19, p)); \\ _Michel Marcus_, Jun 23 2019
%K nonn
%O 1,1
%A _N. J. A. Sloane_.
%E Name clarified by _Michel Marcus_, Jun 23 2019
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