A009415 - OEIS

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A009415

Expansion of log(1+x)*cosh(tanh(x)).

0, 1, -1, 5, -12, 9, -105, 1413, -8176, 42801, -442665, 5165445, -54556524, 637139385, -8293744641, 113478922053, -1717525727040, 28284932778977, -475222905120177, 8340834063368709, -159725733100784940, 3244894614657423849

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OFFSET

0,4

LINKS

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

FORMULA

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

MATHEMATICA

Log[ 1+x ]*Cosh[ Tanh[ x ] ]

CoefficientList[Series[Cosh[Tanh[x]]*Log[1 + x], {x, 0, 20}], x] * Range[0, 20]! (* Vaclav Kotesovec, Jan 23 2015 *)

CROSSREFS

Sequence in context: A070368 A066326 A015242 * A251935 A195031 A265028

Adjacent sequences: A009412 A009413 A009414 * A009416 A009417 A009418

KEYWORD

sign,easy

AUTHOR

R. H. Hardin

EXTENSIONS

Extended with signs by Olivier Gérard, Mar 15 1997

STATUS

approved