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 A192613 #4 Mar 30 2012 18:57:36
%S A192613 1,2,3,4,11,17,19,41,139,251,307,379,587,1699,3371
%N A192613 Monotonic ordering of set S generated by these rules: if x and y are in S and x^2+2y^2 is a prime, then x^2+2y^2 is in S, and 1, 2, and 4 are in S.
%C A192613 See the discussions at A192476 and A192580.
%t A192613 start = {1, 2, 4}; primes = Table[Prime[n], {n, 1, 20000}];
%t A192613 f[x_, y_] := If[MemberQ[primes, x^2 + 2 y^2], x^2 + 2 y^2]
%t A192613 b[x_] :=
%t A192613 Block[{w = x},
%t A192613 Select[Union[
%t A192613 Flatten[AppendTo[w,
%t A192613 Table[f[w[[i]], w[[j]]], {i, 1, Length[w]}, {j, 1,
%t A192613 Length[w]}]]]], # < 30000 &]];
%t A192613 t = FixedPoint[b, start] (* A192613 *)
%Y A192613 Cf. A192612, A192476, A192580.
%K A192613 nonn,fini,full
%O A192613 1,2
%A A192613 _Clark Kimberling_, Jul 05 2011