A009319 - OEIS

A009319

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

0, 1, -2, 4, -17, 93, -649, 5381, -51778, 565957, -6930141, 93992413, -1399244076, 22689478823, -398164266655, 7519118564551, -152058873978384, 3278894568674073, -75103386737309385, 1821102601528126265

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OFFSET

0,3

LINKS

Table of n, a(n) for n=0..19.

FORMULA

a(n) ~ (n-1)! * (-1)^(n+1) / r^n, where r = 0.7426973079865501887067225087448265047287233394318... is the root of the equation exp(1/cos(r))*(r-1) = -1. - Vaclav Kotesovec, Jan 24 2015

MATHEMATICA

Log[ 1+Log[ 1+x ]*Cos[ x ] ]

CoefficientList[Series[Log[1 + Cos[x]*Log[1 + x]], {x, 0, 20}], x] * Range[0, 20]! (* Vaclav Kotesovec, Jan 24 2015 *)

CROSSREFS

Sequence in context: A112005 A212581 A305786 * A347724 A009323 A307125

Adjacent sequences: A009316 A009317 A009318 * A009320 A009321 A009322

KEYWORD

sign,easy

AUTHOR

R. H. Hardin

EXTENSIONS

Extended with signs by Olivier Gérard, Mar 15 1997

STATUS

approved