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 A361846 #16 Apr 07 2023 08:57:04
%S A361846 1,3,24,243,2973,41676,652662,11228556,209674050,4211011422,
%T A361846 90309000630,2056139084544,49460437075896,1251936022103679,
%U A361846 33228751234896060,922028391785300940,26676362307801924057,802875670635086298600
%N A361846 a(n) = Sum_{k=0..n} (-9)^k * binomial(-1/3,k) * binomial(n*k,n-k).
%H A361846 Winston de Greef, <a href="/A361846/b361846.txt">Table of n, a(n) for n = 0..451</a>
%F A361846 a(n) = [x^n] 1/(1 - 9*x*(1+x)^n)^(1/3).
%o A361846 (PARI) a(n) = sum(k=0, n, (-9)^k*binomial(-1/3, k)*binomial(n*k, n-k));
%Y A361846 Main diagonal of A361839.
%Y A361846 Cf. A361829, A361847.
%K A361846 nonn
%O A361846 0,2
%A A361846 _Seiichi Manyama_, Mar 27 2023