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 A384026 #10 May 17 2025 14:01:50
%S A384026 1,0,0,8,1188,240480,68630824,26730127872,13715719388784,
%T A384026 8994742935058880,7351374493516431744,7333037983443263351040,
%U A384026 8772990646534399559904256,12403600039078715891159873280,20464777911173655904724421045504,38976211807455406964301439206318080
%N A384026 a(n) = [x^(2*n)] Product_{k=0..n-1} (1 + k*x)^3.
%F A384026 a(n) = Sum_{i, j, k>=0 and i+j+k=n} |Stirling1(n,i) * Stirling1(n,j) * Stirling1(n,k)|.
%o A384026 (PARI) a(n) = sum(i=0, n, sum(j=0, n-i, abs(stirling(n, i, 1)*stirling(n, j, 1)*stirling(n, n-i-j, 1))));
%Y A384026 Cf. A342111, A384027.
%Y A384026 Cf. A384018.
%K A384026 nonn
%O A384026 0,4
%A A384026 _Seiichi Manyama_, May 17 2025