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 A366501 #10 Oct 11 2023 08:41:37
%S A366501 1,1,-7,49,-399,3633,-35511,363937,-3858079,41951521,-465296487,
%T A366501 5243459409,-59865074223,690979478481,-8049598938135,94522387901505,
%U A366501 -1117615459764031,13294669980012865,-158995530738069703,1910555096402418545,-23056131790988675279
%N A366501 G.f. A(x) satisfies A(x) = 1 + x / ((1+x)^4*A(x)^3).
%F A366501 G.f.: A(x) = 1/B(-x) where B(x) is the g.f. of A213336.
%F A366501 a(n) = (-1)^(n-1) * Sum_{k=0..n} binomial(n+3*k-1,n-k) * binomial(4*k-1,k) / (4*k-1).
%o A366501 (PARI) a(n) = (-1)^(n-1)*sum(k=0, n, binomial(n+3*k-1, n-k)*binomial(4*k-1, k)/(4*k-1));
%Y A366501 Cf. A001006, A366221, A366272, A366273, A366495, A366496, A366497, A366498, A366499, A366500.
%Y A366501 Cf. A213336.
%K A366501 sign
%O A366501 0,3
%A A366501 _Seiichi Manyama_, Oct 11 2023