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 A009374 #13 Jun 22 2015 22:28:09
%S A009374 0,1,-3,10,-40,205,-1287,9714,-85384,859889,-9751651,123102098,
%T A009374 -1711387808,25985945453,-427828028695,7591346835562,-144408464041712,
%U A009374 2931676572255297,-63262735545686819,1445955290624608506
%N A009374 Expansion of log(1+tan(x))/exp(x).
%F A009374 a(n) ~ (n-1)! * (-1)^(n+1) * exp(Pi/4) * (4/Pi)^n. - _Vaclav Kotesovec_, Jan 23 2015
%t A009374 Log[ 1+Tan[ x ] ]/Exp[ x ]
%t A009374 CoefficientList[Series[Log[1 + Tan[x]]/E^x, {x, 0, 20}], x] * Range[0, 20]! (* _Vaclav Kotesovec_, Jan 23 2015 *)
%K A009374 sign,easy
%O A009374 0,3
%A A009374 _R. H. Hardin_
%E A009374 Extended with signs by _Olivier Gérard_, Mar 15 1997