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 A366436 #9 Oct 10 2023 05:08:51
%S A366436 1,1,-6,36,-272,2304,-20880,198080,-1942080,19521792,-200101376,
%T A366436 2083538688,-21976624128,234321952768,-2521446660096,27347192389632,
%U A366436 -298643542716416,3280990949720064,-36238161907974144,402146115064233984,-4481721683926056960
%N A366436 G.f. A(x) satisfies A(x) = 1 + x * ((1 - x) / A(x))^3.
%F A366436 a(n) = (-1)^(n-1) * Sum_{k=0..n} binomial(4*k-1,k) * binomial(3*k,n-k) / (4*k-1).
%o A366436 (PARI) a(n) = (-1)^(n-1)*sum(k=0, n, binomial(4*k-1, k)*binomial(3*k, n-k)/(4*k-1));
%Y A366436 Partial sums give A366365.
%Y A366436 Cf. A366431, A366432, A366433, A366434, A366435, A366437.
%K A366436 sign
%O A366436 0,3
%A A366436 _Seiichi Manyama_, Oct 09 2023