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 A009389 #18 Jun 22 2015 22:28:47
%S A009389 0,1,-1,3,-4,5,-1,7,-64,9,1319,11,-49204,13,2653559,15,-196707424,17,
%T A009389 19194804719,19,-2385684870724,21,367985503366799,23,
%U A009389 -68980888889771104,25,15445553274667315799,27,-4071626956018456576564,29
%N A009389 Expansion of log(1+tanh(x))*cosh(x).
%t A009389 With[{nn=30},CoefficientList[Series[Log[1+Tanh[x]]*Cosh[x],{x,0,nn}], x]Range[0,nn]!] (* _Harvey P. Dale_, Mar 09 2012 *)
%Y A009389 From _Johannes W. Meijer_, May 24 2009: (Start)
%Y A009389 The a(2*n) sequence equals the second left hand column of A160485 divided by two.
%Y A009389 (End)
%K A009389 sign,easy
%O A009389 0,4
%A A009389 _R. H. Hardin_
%E A009389 Extended with signs by _Olivier Gérard_, Mar 15 1997