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 A101610 #5 Apr 30 2014 01:26:48
%S A101610 1,2,9,36,220,1320,10500,84000,828576,8285760,97796160,1173553920,
%T A101610 16145775360,226040855040,3554072121600,56865153945600,
%U A101610 1006228442419200,18112111963545600,356294637348249600
%N A101610 n! * Sum[k=1..ceiling(n/2), 1/k].
%t A101610 Table[n!Sum[1/k,{k,1,Ceiling[n/2]}],{n,20}] (* _Harvey P. Dale_, Apr 25 2011 *)
%Y A101610 Cf. A101609, A101611, A101612, A101613, A000254, A046673, A052517.
%K A101610 nonn,easy
%O A101610 1,2
%A A101610 _Ralf Stephan_, Dec 10 2004