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 A366326 #19 Oct 22 2023 17:10:18
%S A366326 1,2,-3,14,-78,479,-3131,21372,-150588,1087057,-7998295,59763129,
%T A366326 -452257495,3459109408,-26697940390,207672518808,-1626400971710,
%U A366326 12813379464399,-101482102525511,807524595076284,-6452856224076654,51760509258982478,-416620859045829372
%N A366326 G.f. satisfies A(x) = (1 + x) * (1 + x/A(x)^2).
%H A366326 Winston de Greef, <a href="/A366326/b366326.txt">Table of n, a(n) for n = 0..1067</a>
%F A366326 a(n) = (-1)^(n-1) * Sum_{k=0..n} binomial(3*k-1,k) * binomial(n+k-2,n-k)/(3*k-1).
%o A366326 (PARI) a(n) = (-1)^(n-1)*sum(k=0, n, binomial(3*k-1, k)*binomial(n+k-2, n-k)/(3*k-1));
%Y A366326 Cf. A073157, A364336, A364337, A364338, A364339, A366325, A366327, A366328.
%Y A366326 Cf. A006013, A364393.
%K A366326 sign
%O A366326 0,2
%A A366326 _Seiichi Manyama_, Oct 07 2023