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 A361932 #31 Oct 15 2023 09:25:48
%S A361932 1,0,0,1,3,6,13,33,84,208,522,1341,3476,9042,23673,62426,165504,
%T A361932 440664,1178168,3162357,8517681,23013294,62356329,169408107,461366499,
%U A361932 1259311824,3444497550,9439766700,25916832981,71274793968,196325540206,541579442133
%N A361932 G.f. A(x) satisfies A(x) = 1 + (x * A(x) / (1 - x))^3.
%F A361932 a(n) = Sum_{k=0..floor(n/3)} binomial(n-1,n-3*k) * binomial(3*k,k) / (2*k+1).
%o A361932 (PARI) a(n) = sum(k=0, n\3, binomial(n-1, n-3*k)*binomial(3*k, k)/(2*k+1));
%Y A361932 Partial sums give A071879.
%Y A361932 Cf. A000245, A213282, A364403.
%K A361932 nonn
%O A361932 0,5
%A A361932 _Seiichi Manyama_, Oct 15 2023