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 A372086 #7 Apr 18 2024 09:32:09
%S A372086 1,2,12,84,664,5624,49928,458480,4318896,41503168,405267840,
%T A372086 4009684608,40109536992,404977089792,4121810315584,42243756499328,
%U A372086 435593319238144,4515817056202496,47040399766319360,492117122988795392,5168258741713256960
%N A372086 G.f. A(x) satisfies A(x) = 1/( 1 - 4*x*(1 + x)*A(x) )^(1/2).
%F A372086 a(n) = Sum_{k=0..n} 4^k * binomial(3*k/2-1/2,k) * binomial(k,n-k)/(k+1).
%o A372086 (PARI) a(n) = sum(k=0, n, 4^k*binomial(3*k/2-1/2, k)*binomial(k, n-k)/(k+1));
%Y A372086 Cf. A006139, A372037.
%K A372086 nonn
%O A372086 0,2
%A A372086 _Seiichi Manyama_, Apr 17 2024