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 A371586 #14 Mar 29 2024 15:21:43
%S A371586 1,2,13,106,986,9898,104535,1144630,12876908,147937396,1728352171,
%T A371586 20471245898,245254954252,2966792716710,36186910210761,
%U A371586 444559817944096,5495828249436652,68318636646858588,853455362282694440,10708603125245767280,134897492549870974674
%N A371586 G.f. satisfies A(x) = ( 1 + x*A(x)^2 * (1 + x*A(x)^2)^2 )^2.
%F A371586 If g.f. satisfies A(x) = ( 1 + x*A(x)^(t/r) * (1 + x*A(x)^(u/r))^s )^r, then a(n) = r * Sum_{k=0..n} binomial(t*k+u*(n-k)+r,k) * binomial(s*k,n-k)/(t*k+u*(n-k)+r).
%o A371586 (PARI) a(n, r=2, s=2, t=4, u=4) = r*sum(k=0, n, binomial(t*k+u*(n-k)+r, k)*binomial(s*k, n-k)/(t*k+u*(n-k)+r));
%Y A371586 Cf. A367282.
%K A371586 nonn
%O A371586 0,2
%A A371586 _Seiichi Manyama_, Mar 28 2024