A009317 Expansion of log(1+log(1+x))/cosh(x).

0, 1, -2, 4, -23, 183, -1459, 13592, -153348, 1975117, -28287606, 449154660, -7849907559, 149555531331, -3083839320171, 68448665226744, -1627353764342224, 41258541219292569, -1111163801421888834

Offset

0,3

Links

Table of n, a(n) for n=0..18.

Formula

a(n) ~ (n-1)! * (-1)^(n+1) / (cosh(1-exp(-1)) * (1-exp(-1))^n). - Vaclav Kotesovec, Jan 23 2015

Mathematica

With[{nn=20}, CoefficientList[Series[Log[1+Log[1+x]]/Cosh[x], {x, 0, nn}], x]Range[0, nn]!] (* Harvey P. Dale, Jan 23 2012 *)

Crossrefs

Sequence in context: A173352 A366224 A009313 * A209024 A081680 A269573

Adjacent sequences: A009314 A009315 A009316 * A009318 A009319 A009320

Keyword

sign,easy

Author

R. H. Hardin

Extensions

Extended with signs by Olivier Gérard, Mar 15 1997

Status

approved