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 A366237 #10 Oct 05 2023 08:35:05
%S A366237 1,2,7,33,161,843,4601,25896,149254,876480,5225616,31547730,192470212,
%T A366237 1184804588,7349888208,45902094845,288368474907,1821096958308,
%U A366237 11554270204142,73615309821574,470795634833760,3021222108762826,19448517295201332
%N A366237 G.f. A(x) satisfies A(x) = 1 + x + x*(1 + x)^3*A(x)^2.
%F A366237 G.f.: 2*(1+x) / (1 + sqrt(1-4*x*(1+x)^4)).
%F A366237 a(n) = Sum_{k=0..n} binomial(4*k+1,n-k) * binomial(2*k,k)/(k+1).
%o A366237 (PARI) a(n) = sum(k=0, n, binomial(4*k+1, n-k)*binomial(2*k, k)/(k+1));
%Y A366237 Cf. A073157, A366236, A366238.
%Y A366237 Cf. A000108.
%K A366237 nonn
%O A366237 0,2
%A A366237 _Seiichi Manyama_, Oct 05 2023