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 A369442 #10 Jan 23 2024 11:14:25
%S A369442 1,1,1,3,11,31,84,261,865,2815,9131,30339,102681,349376,1193993,
%T A369442 4111947,14263137,49720513,174040102,611770893,2158954383,7645030641,
%U A369442 27153898487,96719683491,345414958227,1236555046701,4436564115556,15950469680836,57455730349552
%N A369442 Expansion of (1/x) * Series_Reversion( x / ((1+x) * (1+x^3)^2) ).
%H A369442 <a href="/index/Res#revert">Index entries for reversions of series</a>
%F A369442 a(n) = (1/(n+1)) * Sum_{k=0..floor(n/3)} binomial(2*n+2,k) * binomial(n+1,n-3*k).
%o A369442 (PARI) my(N=30, x='x+O('x^N)); Vec(serreverse(x/((1+x)*(1+x^3)^2))/x)
%o A369442 (PARI) a(n, s=3, t=2, u=1) = sum(k=0, n\s, binomial(t*(n+1), k)*binomial(u*(n+1), n-s*k))/(n+1);
%Y A369442 Cf. A198951.
%K A369442 nonn
%O A369442 0,4
%A A369442 _Seiichi Manyama_, Jan 23 2024