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%I #17 Oct 30 2013 09:37:21
%S 1,1,1,2,5,16,61,216,937,6400,41881,125696,259181,18156672,225924245,
%T -930421504,-25529526319,394852151296,8376428366257,-97538559528960,
%U -2542034772205739,37824762737852416
%N E.g.f.: exp(tan(arcsinh(x))).
%F a(n) ~ 4*n^(n-1) * sin(n*Pi/2 - tanh(Pi/2)) / (exp(n)*(1+cosh(Pi))). - _Vaclav Kotesovec_, Oct 30 2013
%e exp(tan(arcsinh(x))) = 1 +x +1/2!*x^2 +2/3!*x^3 +5/4!*x^4 +16/5!*x^5 ...
%t With[{nn=30},CoefficientList[Series[Exp[Tan[ArcSinh[x]]],{x,0,nn}],x] Range[0,nn]!] (* _Harvey P. Dale_, Oct 05 2013 *)
%Y A012167(n)=A012159(2*n)
%K sign
%O 0,4
%A Patrick Demichel (patrick.demichel(AT)hp.com)
%E More terms from _N. J. A. Sloane_, Aug 27 2006
%E Definition clarified by _Harvey P. Dale_, Oct 05 2013