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 A193063 #11 Nov 21 2013 13:11:56
%S A193063 2,3,5,7,11,13
%N A193063 Primes p for which there is no prime q == 1 (mod 3) that is smaller than p and is a quadratic residue modulo p.
%C A193063 Gica proved that if p is a prime different from 2, 3, 5, 7, 11, 13, then a prime q < p exists which is a quadratic residue modulo p and q == 1 (mod 3). His paper has not yet been published, but see A192578 for a reference, link, and examples of a similar result.
%t A193063 piMax = 100; quadQ[q_, p_] := Length[ Select[ Table[x^2, {x, 1, Floor[p/2]}], Mod[#, p] == q & , 1]] == 1; noPrimeQ[p_] := Select[ Table[ Prime[n], {n, 1, PrimePi[p]}], Mod[#, 3] == 1 && quadQ[#, p] &] === {}; Select[ Table[ Prime[n], {n, 1, piMax}], noPrimeQ] (* _Jean-François Alcover_, Oct 03 2011 *)
%Y A193063 Cf. A192578, A192579, A193064.
%K A193063 nonn,fini,full
%O A193063 1,1
%A A193063 _Jonathan Sondow_, Jul 15 2011