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 A101611 #12 Dec 07 2019 12:18:24
%S A101611 1,3,5,26,94,684,3828,35664,270576,3068640,29400480,392722560,
%T A101611 4546558080,69878833920,948550176000,16484477184000,256697973504000,
%U A101611 4976250951168000,87435019510272000,1870345490614272000
%N A101611 a(n) = n! * Sum_{k=ceiling(n/2)..n} 1/k.
%F A101611 E.g.f: (log(1 - x) - x*log(1 - x^2))/(x - 1). - _Benedict W. J. Irwin_, Apr 25 2017
%t A101611 Rest@Table[CoefficientList[Series[(Log[1-x]-x*Log[1-x^2])/(x-1),{x, 0, 20}],x][[n]](n-1)!,{n, 1, 20}] (* _Benedict W. J. Irwin_, Apr 25 2017 *)
%o A101611 (PARI) a(n) = n! * sum(k=ceil(n/2), n, 1/k); \\ _Michel Marcus_, Apr 25 2017
%o A101611 (Python)
%o A101611 import math
%o A101611 from sympy import factorial
%o A101611 def a(n): return factorial(n)*sum([1/k for k in range(int(math.ceil(n/2)), n + 1)]) # _Indranil Ghosh_, Apr 25 2017
%Y A101611 Cf. A101609, A101610, A101612, A101613, A000254, A046673, A052517.
%K A101611 nonn,easy
%O A101611 1,2
%A A101611 _Ralf Stephan_, Dec 10 2004