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 A366327 #15 Oct 07 2023 08:45:40
%S A366327 1,2,-5,33,-260,2263,-20979,203124,-2030121,20786694,-216928144,
%T A366327 2298911699,-24673591005,267644087524,-2929602893537,32317666058508,
%U A366327 -358931896710948,4010200327457883,-45040693394259858,508253687784232108,-5759468659295939684
%N A366327 G.f. satisfies A(x) = (1 + x) * (1 + x/A(x)^3).
%F A366327 a(n) = (-1)^(n-1) * Sum_{k=0..n} binomial(4*k-1,k) * binomial(n+2*k-2,n-k)/(4*k-1).
%o A366327 (PARI) a(n) = (-1)^(n-1)*sum(k=0, n, binomial(4*k-1, k)*binomial(n+2*k-2, n-k)/(4*k-1));
%Y A366327 Cf. A073157, A364336, A364337, A364338, A364339, A366325, A366326, A366328.
%Y A366327 Cf. A006632, A364407.
%K A366327 sign
%O A366327 0,2
%A A366327 _Seiichi Manyama_, Oct 07 2023