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 A001990 M3953 N1632 #27 Feb 04 2022 02:01:53
%S A001990 5,29,29,29,29,29,29,29,23669,23669,23669,23669,23669,23669,1508789,
%T A001990 5025869,9636461,9636461,9636461,37989701,37989701,37989701,37989701,
%U A001990 37989701,240511301,240511301
%N A001990 Let p be the n-th odd prime. a(n) is the least prime congruent to 5 modulo 8 such that Legendre(-a(n), q) = -Legendre(-2, q) for all odd primes q <= p.
%C A001990 Numbers so far are all congruent to 5 (mod 24). - _Ralf Stephan_, Jul 07 2003
%D A001990 N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
%D A001990 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
%H A001990 D. H. Lehmer, E. Lehmer and D. Shanks, <a href="https://doi.org/10.1090/S0025-5718-1970-0271006-X">Integer sequences having prescribed quadratic character</a>, Math. Comp., 24 (1970), 433-451.
%H A001990 D. H. Lehmer, E. Lehmer and D. Shanks, <a href="/A002189/a002189.pdf">Integer sequences having prescribed quadratic character</a>, Math. Comp., 24 (1970), 433-451 [Annotated scanned copy]
%o A001990 (PARI) isok(p, oddpn) = {forprime(q=3, oddpn, if (kronecker(p, q) != -kronecker(-2, q), return (0));); return (1);}
%o A001990 a(n) = {oddpn = prime(n+1); forprime(p=3, , if ((p%8) == 5, if (isok(p, oddpn), return (p));););} \\ _Michel Marcus_, Oct 18 2017
%Y A001990 Cf. A001988.
%K A001990 nonn
%O A001990 1,1
%A A001990 _N. J. A. Sloane_
%E A001990 Better name from _Sean A. Irvine_, Mar 06 2013
%E A001990 Name and offset corrected by _Michel Marcus_, Oct 18 2017