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 A383163 #12 Apr 18 2025 10:05:53
%S A383163 0,0,1,9,75,690,7290,88536,1223628,19019664,328908720,6268688448,
%T A383163 130615236576,2954657491968,72128519473920,1890266313945600,
%U A383163 52937770062975744,1577901064699594752,49877742373556336640,1666688195869095124992,58704547943954039672832
%N A383163 Expansion of e.g.f. log(1 - (exp(2*x) - 1)/2)^2 / 2.
%F A383163 a(n) = Sum{k=2..n} 2^(n-k) * Stirling2(n,k) * |Stirling1(k,2)|.
%F A383163 a(n) ~ sqrt(Pi) * 2^(n + 1/2) * n^(n - 1/2) * log(n) / (exp(n) * log(3)^n). - _Vaclav Kotesovec_, Apr 18 2025
%o A383163 (PARI) a(n) = sum(k=2, n, 2^(n-k)*stirling(n, k, 2)*abs(stirling(k, 2, 1)));
%Y A383163 Column k=2 of A383149.
%Y A383163 Cf. A000254.
%K A383163 nonn
%O A383163 0,4
%A A383163 _Seiichi Manyama_, Apr 18 2025