A009682 Expansion of tan(sinh(x))*sin(x).

0, 2, 8, 168, 6208, 365984, 31759232, 3799039104, 599327352832, 120551382086144, 30112348370954240, 9144842254707320832, 3318219571077818269696, 1417778434388262802202624

Offset

0,2

Links

Table of n, a(n) for n=0..13.

Formula

a(n) ~ (2*n)! * 4 * sin(arcsinh(Pi/2)) / (sqrt(4+Pi^2) * arcsinh(Pi/2)^(2*n+1)). - Vaclav Kotesovec, Jan 23 2015

Mathematica

nn = 20; Table[(CoefficientList[Series[Sin[x]*Tan[Sinh[x]], {x, 0, 2*nn}], x] * Range[0, 2*nn]!)[[n]], {n, 1, 2*nn+1, 2}] (* Vaclav Kotesovec, Jan 23 2015 *)

Crossrefs

Sequence in context: A175538 A397075 A009606 * A076548 A167009 A350808

Adjacent sequences: A009679 A009680 A009681 * A009683 A009684 A009685

Keyword

nonn

Author

R. H. Hardin

Extensions

Extended and signs tested Mar 15 1997 by Olivier Gérard.

Previous incomplete Mathematica program deleted by Harvey P. Dale, Apr 28 2025

Status

approved