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 A375660 #10 Sep 01 2024 09:35:52
%S A375660 1,0,4,6,80,370,4152,34034,413632,4744674,66354680,954512482,
%T A375660 15454225536,263909265074,4898255210968,96284064551250,
%U A375660 2022022344889472,44858682139345090,1052826609589372152,25994393541984673154,674563101823606851520,18337775305498096349202
%N A375660 Expansion of e.g.f. 1 / (1 - x * (exp(x) - 1))^2.
%F A375660 E.g.f.: B(x)^2, where B(x) is the e.g.f. of A052848.
%F A375660 a(n) = n! * Sum_{k=0..floor(n/2)} (k+1)! * Stirling2(n-k,k)/(n-k)!.
%o A375660 (PARI) my(N=30, x='x+O('x^N)); Vec(serlaplace(1/(1-x*(exp(x)-1))^2))
%o A375660 (PARI) a(n) = n!*sum(k=0, n\2, (k+1)!*stirling(n-k, k, 2)/(n-k)!);
%Y A375660 Cf. A052848, A375661.
%Y A375660 Cf. A005649.
%K A375660 nonn
%O A375660 0,3
%A A375660 _Seiichi Manyama_, Aug 23 2024