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 A012584 #8 Oct 31 2013 05:23:43
%S A012584 1,1,3,9,33,145,715,3801,21889,140001,974803,6947017,50720417,
%T A012584 421135793,3950147227,33562929817,240061039105,2672302901185,
%U A012584 45695167547043,388308372326665,-1858226878271967,9709607588675537
%N A012584 exp(arcsinh(x)*exp(x))=1+x+3/2!*x^2+9/3!*x^3+33/4!*x^4+145/5!*x^5...
%F A012584 E.g.f.: (x+sqrt(1+x^2))^(exp(x)). - _Vaclav Kotesovec_, Oct 31 2013
%F A012584 a(n) ~ 2*sin(n*Pi/2-1-Pi*cos(1)/2) * exp(-Pi*sin(1)/2) * n^(n-1) / exp(n). - _Vaclav Kotesovec_, Oct 31 2013
%t A012584 CoefficientList[Series[Exp[ArcSinh[x]*Exp[x]], {x, 0, 20}], x]* Range[0, 20]! (* _Vaclav Kotesovec_, Oct 31 2013 *)
%K A012584 sign
%O A012584 0,3
%A A012584 Patrick Demichel (patrick.demichel(AT)hp.com)