A009409 Expansion of log(1+x)*cos(tanh(x)).

0, 1, -1, -1, 0, 49, -165, -393, -504, 66753, -414225, 21295, -15435816, 561504241, -5685997317, 34755442407, -746778152400, 18822723988481, -281687621998401, 3781703063806559, -80079140948241200, 1899387285774263089

Offset

0,6

Links

Table of n, a(n) for n=0..21.

Formula

a(n) ~ (n-1)! * (-1)^(n+1) * cos(tanh(1)). - Vaclav Kotesovec, Jan 23 2015

Mathematica

With[{nn=25}, CoefficientList[Series[Log[1+x]*Cos[Tanh[x]], {x, 0, nn}], x]Range[0, nn]!] (* Harvey P. Dale, Oct 11 2011 *)

Crossrefs

Sequence in context: A338011 A066551 A134210 * A009431 A226353 A074216

Adjacent sequences: A009406 A009407 A009408 * A009410 A009411 A009412

Keyword

sign,easy

Author

R. H. Hardin

Extensions

Extended with signs by Olivier Gérard, Mar 15 1997

Status

approved