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exp(arctanh(x)*exp(x))=1+x+3/2!*x^2+12/3!*x^3+57/4!*x^4+340/5!*x^5...
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%I #10 Nov 21 2013 12:46:01

%S 1,1,3,12,57,340,2305,18186,158977,1560840,16695553,196272142,

%T 2483596577,34036624700,497515462561,7792454528002,129248702613505,

%U 2278494692749840,42291311707716609,828953188249846678

%N exp(arctanh(x)*exp(x))=1+x+3/2!*x^2+12/3!*x^3+57/4!*x^4+340/5!*x^5...

%F a(n) ~ (n-1)! * (2*n)^(exp(1)/2) / GAMMA(exp(1)/2). - _Vaclav Kotesovec_, Oct 24 2013

%t With[{nn=20},CoefficientList[Series[Exp[ArcTanh[x]Exp[x]],{x,0,nn}], x]Range[0,nn]!] (* _Harvey P. Dale_, Jan 14 2012 *)

%K nonn

%O 0,3

%A Patrick Demichel (patrick.demichel(AT)hp.com)