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 A013109 #6 Jul 19 2014 18:16:11
%S A013109 2,-11,441,-48897,10711449,-3898352493,2124846180765,
%T A013109 -1619764201737297,1645104402411921297,-2147066174256624128277,
%U A013109 3501336873746919748187493,-6976563529004472877778185497
%N A013109 arcsinh(arcsinh(x)+arctan(x))=2*x-11/3!*x^3+441/5!*x^5-48897/7!*x^7...
%t A013109 With[{nn=30},Take[CoefficientList[Series[ArcSinh[ArcSinh[x]+ArcTan[x]],{x,0,nn}],x] Range[0,nn-1]!,{2,-1,2}]] (* _Harvey P. Dale_, Jul 19 2014 *)
%K A013109 sign
%O A013109 0,1
%A A013109 Patrick Demichel (patrick.demichel(AT)hp.com)