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 A382921 #11 Apr 09 2025 07:29:09
%S A382921 1,3,24,199,1776,16713,163429,1644852,16929576,177384877,1885842105,
%T A382921 20292695751,220595817213,2418988309494,26726104358958,
%U A382921 297226167487469,3324654200094495,37379224636055040,422182501323170275,4788001977121735326,54502930562354983641
%N A382921 G.f. A(x) satisfies A(x) = 1/( 1 - x*A(x) / (1-x)^3 )^3.
%F A382921 G.f. A(x) satisfies A(x) = ( 1 + x*A(x)^(4/3) / (1-x)^3 )^3.
%F A382921 If g.f. satisfies A(x) = ( 1 + x*A(x)^(t/r) / (1 - x*A(x)^(u/r))^s )^r, then a(n) = r * Sum_{k=0..n} binomial(t*k+u*(n-k)+r,k) * binomial(n+(s-1)*k-1,n-k)/(t*k+u*(n-k)+r).
%F A382921 G.f.: B(x)^3, where B(x) is the g.f. of A382917.
%o A382921 (PARI) a(n, r=3, s=3, t=4, u=0) = r*sum(k=0, n, binomial(t*k+u*(n-k)+r, k)*binomial(n+(s-1)*k-1, n-k)/(t*k+u*(n-k)+r));
%Y A382921 Cf. A360100, A382919.
%Y A382921 Cf. A382615, A382917.
%K A382921 nonn
%O A382921 0,2
%A A382921 _Seiichi Manyama_, Apr 08 2025