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 A101612 #2 Apr 30 2014 01:26:48 %S A101612 3,11,26,154,684,5508,35664,361296,3068640,37383840,392722560, %T A101612 5584394880,69878833920,1135360800000,16484477184000,301158902016000, %U A101612 4976250951168000,100951141777920000,1870345490614272000 %N A101612 n! * Sum[k=floor(n/2)..n, 1/k]. %Y A101612 Cf. A101609, A101610, A101611, A101613, A000254, A046673, A052517. %K A101612 nonn,easy %O A101612 2,1 %A A101612 _Ralf Stephan_, Dec 10 2004