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 A379191 #9 Dec 18 2024 09:27:45
%S A379191 1,4,31,338,4356,61603,923958,14433315,232298914,3825260332,
%T A379191 64140203645,1091364139213,18796605318655,327056343952311,
%U A379191 5740466392321499,101516213938082457,1807045676161156515,32352346658163940698,582185299986049977601,10524395285312191583304,191034444423571726099486
%N A379191 G.f. A(x) satisfies A(x) = (1 + x*A(x))^3/(1 - x*A(x)^3).
%F A379191 a(n) = Sum_{k=0..n} binomial(n+3*k+1,k) * binomial(3*n+6*k+3,n-k)/(n+3*k+1).
%o A379191 (PARI) a(n) = sum(k=0, n, binomial(n+3*k+1, k)*binomial(3*n+6*k+3, n-k)/(n+3*k+1));
%Y A379191 Cf. A379172, A379188, A379190.
%Y A379191 Cf. A307678, A379192.
%K A379191 nonn
%O A379191 0,2
%A A379191 _Seiichi Manyama_, Dec 17 2024