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%I #11 Nov 21 2013 12:46:01
%S 1,2,12,280,13328,1016608,120249536,19735743872,4349101334784,
%T 1233253332705792,437938810884459520,190333673674118699008,
%U 99369086035110941036544,61369835997419856216006656
%N exp(arctanh(x)*tanh(x)) = 1+2/2!*x^2+12/4!*x^4+280/6!*x^6+13328/8!*x^8...
%F a(n) ~ 2 * (2*n-1)! * (4*n)^c / GAMMA(c), where c = tanh(1)/2 = (exp(2)-1)/(exp(2)+1)/2. - _Vaclav Kotesovec_, Oct 24 2013
%t With[{nn=30},Take[CoefficientList[Series[Exp[ArcTanh[x]Tanh[x]],{x,0,nn}], x]Range[0,nn]!,{1,-1,2}]] (* _Harvey P. Dale_, Apr 21 2012 *)
%K nonn
%O 0,2
%A Patrick Demichel (patrick.demichel(AT)hp.com)
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