This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A038888 #12 Jul 08 2025 22:26:32 %S A038888 13,19,23,29,31,37,41,47,73,79,83,89,97,101,107,139,149,151,157,167, %T A038888 193,199,211,227,263,269,271,277,281,313,331,337,347,373,379,383,389, %U A038888 397,401,433,439,443,449,457,461 %N A038888 Primes p such that 15 is not a square mod p. %C A038888 Subset of A040136. %C A038888 Also primes p such that p divides 5^(p-1)/2 + 3^(p-1)/2. - _Cino Hilliard_, Sep 06 2004 %H A038888 Vincenzo Librandi, <a href="/A038888/b038888.txt">Table of n, a(n) for n = 1..1000</a> %t A038888 Select[Prime@Range[120], JacobiSymbol[15, #] == -1 &] (* _Vincenzo Librandi_, Sep 08 2012 *) %K A038888 nonn %O A038888 1,1 %A A038888 _N. J. A. Sloane_