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 A368968 #21 Jan 14 2024 08:55:51
%S A368968 1,4,26,206,1813,17030,167229,1695920,17624932,186722580,2009077416,
%T A368968 21894695420,241170873096,2680761546396,30032284769832,
%U A368968 338744791093796,3843699928567438,43844993166845920,502497843180361288,5783367971991398760,66815895492710846218
%N A368968 Expansion of (1/x) * Series_Reversion( x * (1-x)^2 * (1-x-x^3)^2 ).
%H A368968 Seiichi Manyama, <a href="/A368968/b368968.txt">Table of n, a(n) for n = 0..917</a>
%H A368968 <a href="/index/Res#revert">Index entries for reversions of series</a>
%F A368968 a(n) = (1/(n+1)) * Sum_{k=0..floor(n/3)} binomial(2*n+k+1,k) * binomial(5*n-2*k+3,n-3*k).
%o A368968 (PARI) my(N=30, x='x+O('x^N)); Vec(serreverse(x*(1-x)^2*(1-x-x^3)^2)/x)
%o A368968 (PARI) a(n, s=3, t=2, u=2) = sum(k=0, n\s, binomial(t*(n+1)+k-1, k)*binomial((t+u+1)*(n+1)-(s-1)*k-2, n-s*k))/(n+1);
%Y A368968 Cf. A368962, A368966, A369011.
%Y A368968 Cf. A368967.
%K A368968 nonn
%O A368968 0,2
%A A368968 _Seiichi Manyama_, Jan 10 2024