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 A296923 #13 Jan 02 2018 16:06:03
%S A296923 2,11,13,17,19,31,37,53,59,71,73,79,97,113,131,137,139,151,157,173,
%T A296923 179,191,193,197,199,211,233,239,251,257,271,277,293,311,313,317,331,
%U A296923 337,353,359,373,379,397,419,431,433,439,457,479,491,499,557,571,577,593,599,613
%N A296923 Primes p such that Legendre(-5,p) = -1.
%C A296923 Primes == 2, 11, 13, 17, or 19 (mod 20). - _Robert Israel_, Dec 27 2017
%H A296923 Robert Israel, <a href="/A296923/b296923.txt">Table of n, a(n) for n = 1..10000</a>
%p A296923 Load the Maple program HH given in A296920. Then run HH(-5,200);
%p A296923 select(isprime, {seq(seq(20*i+j,j=[2,11,13,17,19]),i=0..100)}); # _Robert Israel_, Dec 27 2017
%o A296923 (PARI) lista(nn) = forprime(p=2, nn, if (kronecker(-5,p) == -1, print1(p, ", "))); \\ _Michel Marcus_, Dec 26 2017
%Y A296923 Cf. A296922, A003626.
%K A296923 nonn
%O A296923 1,1
%A A296923 _N. J. A. Sloane_, Dec 25 2017