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 A009765 #13 Jan 27 2014 09:13:01
%S A009765 1,5,101,4689,381769,47849053,8532452397,2051184222377,
%T A009765 639121206054545,250473754883360181,120568689462321176053,
%U A009765 69926680208791530760705,48091629862193464534126041
%N A009765 Expansion of tan(x/cos(x)).
%t A009765 With[{nn=30},Take[CoefficientList[Series[Tan[x/Cos[x]],{x,0,nn}],x] Range[0,nn-1]!,{2,-1,2}]] (* _Harvey P. Dale_, Jan 06 2012 *)
%K A009765 nonn
%O A009765 0,2
%A A009765 _R. H. Hardin_
%E A009765 Extended and signs tested Mar 15 1997 by _Olivier Gérard_.