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 A364764 #9 Aug 06 2023 11:03:36
%S A364764 1,1,1,-2,-14,-27,70,625,1457,-3541,-37403,-98547,207098,2564079,
%T A364764 7448923,-12940485,-190014459,-600991549,827159379,14802832468,
%U A364764 50584687754,-52159768068,-1193457862093,-4384199208207,3090291576246,98618925147291,388126462227091
%N A364764 G.f. satisfies A(x) = 1 + x*A(x)^2 / (1 + x*A(x)^4).
%F A364764 a(n) = (1/n) * Sum_{k=0..n-1} (-1)^k * binomial(n,k) * binomial(2*n+2*k,n-1-k) for n > 0.
%o A364764 (PARI) a(n) = if(n==0, 1, sum(k=0, n-1, (-1)^k*binomial(n, k)*binomial(2*n+2*k, n-1-k))/n);
%Y A364764 Cf. A291534, A363982, A364051.
%Y A364764 Cf. A364739.
%K A364764 sign
%O A364764 0,4
%A A364764 _Seiichi Manyama_, Aug 05 2023