%I #9 Oct 24 2013 16:22:08

%S 1,2,16,398,18072,1465962,169054092,28688618814,6235376638608,

%T 1810793539845714,636329871517885332,282006422882452989030,

%U 145933818284739352119000,91644646853849910546846330

%N exp(arctanh(x)*arcsinh(x)) = 1+2/2!*x^2+16/4!*x^4+398/6!*x^6+18072/8!*x^8...

%F a(n) ~ 2 * (2*n-1)! * (4*n)^(log(1+sqrt(2))/2) / GAMMA(log(1+sqrt(2))/2). - _Vaclav Kotesovec_, Oct 24 2013

%t Table[n!*SeriesCoefficient[Exp[ArcTanh[x]*ArcSinh[x]],{x,0,n}],{n,0,40,2}] (* _Vaclav Kotesovec_, Oct 24 2013 *)

%K nonn

%O 0,2

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