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 A362085 #14 Apr 19 2023 08:04:48
%S A362085 1,3,12,55,315,2106,15946,134730,1253637,12702961,138955146,
%T A362085 1629581955,20371061009,270124999977,3783651174906,55780472480036,
%U A362085 862795543656489,13963065117796548,235845816764772718,4148499020022749151,75841424406989195136
%N A362085 a(n) = Sum_{k=0..n} (-1)^k * binomial(-3,k) * binomial(n*k,n-k).
%H A362085 Seiichi Manyama, <a href="/A362085/b362085.txt">Table of n, a(n) for n = 0..492</a>
%F A362085 a(n) = Sum_{k=0..n} binomial(k+2,k) * binomial(n*k,n-k).
%F A362085 a(n) = [x^n] 1/(1 - x*(1+x)^n)^3.
%o A362085 (PARI) a(n) = sum(k=0, n, binomial(k+2, k)*binomial(n*k, n-k));
%Y A362085 Column k=3 of A362079.
%Y A362085 Cf. A000217, A362088.
%K A362085 nonn
%O A362085 0,2
%A A362085 _Seiichi Manyama_, Apr 08 2023