A012752 exp(arctanh(x)*arcsinh(x)) = 1+2/2!*x^2+16/4!*x^4+398/6!*x^6+18072/8!*x^8...

1, 2, 16, 398, 18072, 1465962, 169054092, 28688618814, 6235376638608, 1810793539845714, 636329871517885332, 282006422882452989030, 145933818284739352119000, 91644646853849910546846330

Offset: 0

Author

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

Keywords

• nonn

Programs

Mathematica

Table[n!*SeriesCoefficient[Exp[ArcTanh[x]*ArcSinh[x]],{x,0,n}],{n,0,40,2}] (* Vaclav Kotesovec, Oct 24 2013 *)

Formula

a(n) ~ 2 * (2*n-1)! * (4*n)^(log(1+sqrt(2))/2) / GAMMA(log(1+sqrt(2))/2). - Vaclav Kotesovec, Oct 24 2013