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 A369480 #11 Jan 24 2024 05:58:32
%S A369480 1,5,38,342,3379,35427,387038,4358119,50222276,589439699,7021368716,
%T A369480 84669873678,1031603223880,12679812357672,157038146685360,
%U A369480 1957792379658934,24549963008189965,309435808369427643,3918185776941808956,49818464846052855850,635788103792527271239
%N A369480 Expansion of (1/x) * Series_Reversion( x / ((1+x)^2 * (1+x+x^2)^3) ).
%H A369480 <a href="/index/Res#revert">Index entries for reversions of series</a>
%F A369480 a(n) = (1/(n+1)) * Sum_{k=0..floor(n/2)} binomial(3*n+3,k) * binomial(5*n-k+5,n-2*k).
%o A369480 (PARI) my(N=30, x='x+O('x^N)); Vec(serreverse(x/((1+x)^2*(1+x+x^2)^3))/x)
%o A369480 (PARI) a(n, s=2, t=3, u=2) = sum(k=0, n\s, binomial(t*(n+1), k)*binomial((t+u)*(n+1)-k, n-s*k))/(n+1);
%Y A369480 Cf. A365128, A369479.
%K A369480 nonn
%O A369480 0,2
%A A369480 _Seiichi Manyama_, Jan 23 2024