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 A365129 #10 Aug 23 2023 08:34:29
%S A365129 1,2,9,44,240,1386,8346,51802,329086,2129330,13984095,92974510,
%T A365129 624568680,4232731050,28904102829,198688337014,1373763563150,
%U A365129 9547516671684,66660156446189,467342635522698,3288691828900768,23220922841177476,164465227646878689
%N A365129 G.f. satisfies A(x) = (1 + x*A(x)*(1 + x*A(x))^2)^2.
%F A365129 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 A365129 (PARI) a(n, s=2, t=2) = sum(k=0, n, binomial(t*(n+1), k)*binomial(s*k, n-k))/(n+1);
%Y A365129 Cf. A161634, A365130.
%Y A365129 Cf. A000108, A365133.
%K A365129 nonn
%O A365129 0,2
%A A365129 _Seiichi Manyama_, Aug 23 2023