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 A012008 #7 Jan 02 2015 16:55:18
%S A012008 1,0,3,30,1113,50460,3693723,359740290,46791574833,7721990402520,
%T A012008 1584990509251443,395230316479830150,117766463267804780553,
%U A012008 41313542582787780576180,16856003114804522914769163
%N A012008 sec(log(cos(x)))= 1+3/4!*x^4+30/6!*x^6+1113/8!*x^8+50460/10!*x^10...
%t A012008 With[{nn=30},Take[CoefficientList[Series[Sec[Log[Cos[x]]],{x,0,nn}],x] Range[0,nn]!,{1,-1,2}]] (* _Harvey P. Dale_, Jan 02 2015 *)
%K A012008 nonn
%O A012008 0,3
%A A012008 Patrick Demichel (patrick.demichel(AT)hp.com)