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 A366238 #9 Oct 05 2023 08:35:09
%S A366238 1,2,8,42,224,1281,7630,46816,294008,1880588,12209474,80251889,
%T A366238 532988530,3571260662,24112334292,163887278097,1120445503036,
%U A366238 7699924478714,53160597794588,368549236730128,2564649436452878,17907555498455680,125426544531794332
%N A366238 G.f. A(x) satisfies A(x) = 1 + x + x*(1 + x)^4*A(x)^2.
%F A366238 G.f.: 2*(1+x) / (1 + sqrt(1-4*x*(1+x)^5)).
%F A366238 a(n) = Sum_{k=0..n} binomial(5*k+1,n-k) * binomial(2*k,k)/(k+1).
%o A366238 (PARI) a(n) = sum(k=0, n, binomial(5*k+1, n-k)*binomial(2*k, k)/(k+1));
%Y A366238 Cf. A073157, A366236, A366237.
%Y A366238 Cf. A000108.
%K A366238 nonn
%O A366238 0,2
%A A366238 _Seiichi Manyama_, Oct 05 2023