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 A009265 #13 Apr 01 2017 13:53:10
%S A009265 1,1,0,-4,-8,32,216,-264,-7552,-9216,349568,1548032,-20281216,
%T A009265 -190744448,1350879232,25395878400,-84211707904,-3862395551744,
%U A009265 -286327484416,674521189158912,2529465981566976,-133945803441307648
%N A009265 Expansion of exp(tanh(x))/cosh(x).
%t A009265 With[{nn=30},CoefficientList[Series[Exp[Tanh[x]]/Cosh[x],{x,0,nn}],x] Range[0,nn]!] (* _Harvey P. Dale_, Nov 13 2014 *)
%K A009265 sign,easy
%O A009265 0,4
%A A009265 _R. H. Hardin_
%E A009265 Extended with signs by _Olivier Gérard_, Mar 15 1997
%E A009265 Prior Mathematica program replaced by _Harvey P. Dale_, Nov 13 2014