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 A384137 #7 May 20 2025 08:53:27
%S A384137 1,15,362,12122,520024,27216936,1681732464,119823343440,9671547654720,
%T A384137 872215286083200,86920331742115200,9485402065890543360,
%U A384137 1124985637517264409600,144084905450972444851200,19819350850103541715507200,2914041773775561429169612800,456069533875430113486232985600
%N A384137 a(n) = (4*n)!/(3*n)! * Sum_{k=1..n} 1/(3*n+k).
%F A384137 a(n) = Sum_{k=0..n} k * (3*n+1)^(k-1) * |Stirling1(n,k)|.
%F A384137 a(n) = n! * [x^n] (-log(1 - x)/(1 - x)^(3*n+1)).
%o A384137 (PARI) a(n) = sum(k=0, n, k*(3*n+1)^(k-1)*abs(stirling(n, k, 1)));
%Y A384137 Cf. A098118, A384136.
%Y A384137 Cf. A382349.
%K A384137 nonn
%O A384137 1,2
%A A384137 _Seiichi Manyama_, May 20 2025