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 A384018 #10 May 17 2025 14:02:05
%S A384018 1,0,3,63,1767,63690,2822740,148810032,9104502015,634448680884,
%T A384018 49622704133175,4305280182748875,410376649359397380,
%U A384018 42633179822414174760,4794685285831034253660,580373328155358031572600,75234419898396217903091151,10398952352945773993329785448,1526704288048697734221906020641
%N A384018 a(n) = [x^n] Product_{k=0..n-1} (1 + k*x)^3.
%F A384018 a(n) = Sum_{0<=i, j, k<=n and i+j+k=2*n} |Stirling1(n,i) * Stirling1(n,j) * Stirling1(n,k)|.
%o A384018 (PARI) a(n) = sum(i=0, n, sum(j=0, 2*n-i, abs(stirling(n, i, 1)*stirling(n, j, 1)*stirling(n, 2*n-i-j, 1))));
%Y A384018 Cf. A342111, A384029.
%Y A384018 Cf. A384026.
%K A384018 nonn
%O A384018 0,3
%A A384018 _Seiichi Manyama_, May 17 2025