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 A365149 #15 Aug 24 2023 07:49:46
%S A365149 1,3,27,301,3780,51030,723170,10611594,159845946,2457515235,
%T A365149 38406398016,608330707740,9744053489754,157564967282709,
%U A365149 2568706865998272,42173100349112852,696692754641035014,11572241797209975966,193153224033985241217
%N A365149 G.f. satisfies A(x) = ( 1 + x*A(x)^2 / (1 - x*A(x))^2 )^3.
%F A365149 If g.f. satisfies A(x) = ( 1 + x*A(x)^2 / (1 - x*A(x))^s )^t, then a(n) = Sum_{k=0..n} binomial(t*(n+k+1),k) * binomial(n+(s-1)*k-1,n-k)/(n+k+1).
%o A365149 (PARI) a(n, s=2, t=3) = sum(k=0, n, binomial(t*(n+k+1), k)*binomial(n+(s-1)*k-1, n-k)/(n+k+1));
%Y A365149 Cf. A011270, A365148.
%Y A365149 Cf. A365121, A365134.
%K A365149 nonn
%O A365149 0,2
%A A365149 _Seiichi Manyama_, Aug 23 2023