A012694 exp(tanh(x)*arcsinh(x))=1+2/2!*x^2-50/6!*x^6+1400/8!*x^8-35222/10!*x^10...

1, 2, 0, -50, 1400, -35222, 94556, 170807390, -38605204656, 8791324177746, -2481630462515900, 912971947568647558, -429970979043182394888, 249025730862440011229306, -171416914808317798189712276

Offset

0,2

Links

Table of n, a(n) for n=0..14.

Formula

a(n) ~ (-1)^(n+1) * tan(1) * 2^(2*n) * n^(2*n-1) / exp(tan(1)*Pi/2 + 2*n). - Vaclav Kotesovec, Nov 01 2013

Mathematica

Table[n!*SeriesCoefficient[Exp[Tanh[x]*ArcSinh[x]], {x, 0, n}], {n, 0, 40, 2}] (* Vaclav Kotesovec, Nov 01 2013 *)

Crossrefs

Sequence in context: A156501 A012420 A140800 * A264437 A306061 A195209

Adjacent sequences: A012691 A012692 A012693 * A012695 A012696 A012697

Keyword

sign

Author

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

Status

approved