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 A365087 #12 Aug 21 2023 08:23:15
%S A365087 1,1,-3,-1,29,-44,-265,1114,1369,-19076,20388,250977,-875281,-2116594,
%T A365087 19136754,-7765108,-306092007,830209808,3388957208,-22266676364,
%U A365087 -8185922076,413223401045,-814031607979,-5513566634947,27558060911119,35395095404776
%N A365087 G.f. satisfies A(x) = 1 + x*A(x) / (1 + x*A(x))^4.
%F A365087 a(n) = Sum_{k=0..n} (-1)^(n-k) * binomial(n,k) * binomial(n+3*k-1,n-k) / (n-k+1).
%o A365087 (PARI) a(n) = sum(k=0, n, (-1)^(n-k)*binomial(n, k)*binomial(n+3*k-1, n-k)/(n-k+1));
%Y A365087 Cf. A090192, A365085, A365086, A365088.
%Y A365087 Cf. A321798, A364737, A365083.
%K A365087 sign
%O A365087 0,3
%A A365087 _Seiichi Manyama_, Aug 21 2023