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 A365131 #9 Aug 23 2023 08:34:21
%S A365131 1,2,11,62,395,2662,18720,135738,1007607,7619456,58488028,454556544,
%T A365131 3569655975,28282204680,225796917864,1814732935968,14670580718486,
%U A365131 119215212413412,973246346463636,7978384233270126,65649676250344747,542031604244083664
%N A365131 G.f. satisfies A(x) = (1 + x*A(x)*(1 + x*A(x))^3)^2.
%F A365131 If g.f. satisfies A(x) = (1 + x*A(x)*(1 + x*A(x))^s)^t, then a(n) = (1/(n+1)) * Sum_{k=0..n} binomial(t*(n+1),k) * binomial(s*k,n-k).
%o A365131 (PARI) a(n, s=3, t=2) = sum(k=0, n, binomial(t*(n+1), k)*binomial(s*k, n-k))/(n+1);
%Y A365131 Cf. A364742, A365132.
%Y A365131 Cf. A137952.
%K A365131 nonn
%O A365131 0,2
%A A365131 _Seiichi Manyama_, Aug 23 2023