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 A366267 #18 Mar 04 2024 01:19:05
%S A366267 1,2,8,56,448,3920,36288,349440,3464448,35125760,362522624,3795914240,
%T A366267 40224968704,430579701760,4648899846144,50568103690240,
%U A366267 553632271155200,6096025799852032,67464070696927232,750003531943903232,8371814935842258944
%N A366267 G.f. A(x) satisfies A(x) = 1 + x + x*A(x)^4.
%F A366267 a(n) = Sum_{k=0..n} binomial(3*k+1,n-k) * binomial(4*k,k)/(3*k+1).
%F A366267 a(n) = A366272(n) + A366272(n-1).
%F A366267 G.f.: A(x) = 1/B(-x) where B(x) is the g.f. of A366365.
%t A366267 nmax = 20; A[_] = 1;
%t A366267 Do[A[x_] = 1 + x + x*A[x]^4 + O[x]^(nmax+1) // Normal, {nmax+1}];
%t A366267 CoefficientList[A[x], x] (* _Jean-François Alcover_, Mar 03 2024 *)
%o A366267 (PARI) a(n) = sum(k=0, n, binomial(3*k+1, n-k)*binomial(4*k, k)/(3*k+1));
%Y A366267 Cf. A025227, A366266, A366268.
%Y A366267 Cf. A366272, A366365.
%K A366267 nonn
%O A366267 0,2
%A A366267 _Seiichi Manyama_, Oct 06 2023