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 A364408 #13 Jul 26 2023 21:00:59
%S A364408 1,2,-8,72,-768,9072,-114240,1502976,-20414208,284083968,-4029438976,
%T A364408 58040074752,-846682968064,12483389708288,-185725854932992,
%U A364408 2784798982701056,-42039464045854720,638415031298588672,-9746180768647217152,149486708349609050112
%N A364408 G.f. satisfies A(x) = 1 + x*(1 + 1/A(x)^4).
%F A364408 G.f.: A(x) = 1/B(-x) where B(x) is the g.f. of A349311.
%F A364408 a(n) = (-1)^(n-1) * (1/n) * Sum_{k=0..n} binomial(n,k) * binomial(n+4*k-2,n-1) for n > 0.
%o A364408 (PARI) a(n) = if(n==0, 1, (-1)^(n-1)*sum(k=0, n, binomial(n, k)*binomial(n+4*k-2, n-1))/n);
%Y A364408 Cf. A364393, A364407, A364409.
%Y A364408 Cf. A349311.
%K A364408 sign
%O A364408 0,2
%A A364408 _Seiichi Manyama_, Jul 23 2023