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 A361638 #24 Jul 13 2023 08:36:40
%S A361638 1,2,14,142,1690,21994,303126,4348102,64235570,970695442,14934154334,
%T A361638 233133082494,3683546302538,58794776161274,946619511627622,
%U A361638 15355445768326710,250717346336174690,4117189670041072930,67956239699290313646,1126763233375565370990
%N A361638 Expansion of g.f. A(x) satisfying A(x) = 1 + x * A(x)^2 * (1 + A(x)^3).
%F A361638 a(n) = Sum_{k=0..n} binomial(n,k) * binomial(2*n+3*k+1,n)/(2*n+3*k+1).
%o A361638 (PARI) a(n) = sum(k=0, n, binomial(n, k)*binomial(2*n+3*k+1, n)/(2*n+3*k+1));
%Y A361638 Cf. A027307, A219534.
%K A361638 nonn,easy
%O A361638 0,2
%A A361638 _Seiichi Manyama_, Jul 13 2023