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 A135865 #2 Mar 30 2012 18:37:07
%S A135865 1,1,2,14,420,52822,26933340,55104785932,451307797531080,
%T A135865 14787550509729279590,1938204238967340827449260,
%U A135865 1016173347424012723201485482596,2131067935523127187022102005624003320
%N A135865 G.f. A(x) satisfies: A(x) = 1 + x*A(4x)^(1/2).
%o A135865 (PARI) {a(n)=local(A=1+x+x*O(x^n));for(i=0,n,A=1+x*subst(A,x,4*x)^(1/2));polcoeff(A,n)}
%Y A135865 Cf. A135866, A135863.
%K A135865 nonn
%O A135865 0,3
%A A135865 _Paul D. Hanna_, Dec 02 2007