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 A114450 #9 Apr 09 2014 10:13:02
%S A114450 0,1,10,252,12176,966240,114341760,18897709824,4160840140800,
%T A114450 1177736213606400,416807049369600000,180368555623280640000,
%U A114450 93711488655948742656000,57572391079539343687680000
%N A114450 a(n)=(2n)!*(sum{k=1...2n}1/k)/(2n+1).
%C A114450 Every term is an integer.
%F A114450 a(n) = A000254(2n)/(2n+1)
%p A114450 seq((2*n)!*(sum(1/k,k=1..2*n))/(2*n+1),n=0..15); - _Emeric Deutsch_, May 15 2006
%t A114450 Table[(2n)! Sum[1/k,{k,2n}]/(2n+1),{n,0,20}] (* _Harvey P. Dale_, Aug 27 2012 *)
%Y A114450 Cf. A000254.
%K A114450 nonn
%O A114450 0,3
%A A114450 _Leroy Quet_, Feb 14 2006
%E A114450 More terms from _Emeric Deutsch_, May 15 2006