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A009122 Expansion of cosh(log(1+log(1+x))). 1
1, 0, 1, -6, 41, -335, 3229, -36036, 457932, -6534384, 103499016, -1802302128, 34227784920, -704076488232, 15595687319640, -370108332316992, 9368461983616128, -251958336139856448, 7174771808983995456 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,4

LINKS

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

FORMULA

a(n) ~ n! * (-1)^n * exp(n) / (2 * (exp(1)-1)^(n+1)). - Vaclav Kotesovec, Jan 22 2015

MATHEMATICA

Cosh[ Log[ 1+Log[ 1+x ] ] ]

CoefficientList[Series[(1 + (1 + Log[1 + x])^2)/(2*(1 + Log[1 + x])), {x, 0, 20}], x] * Range[0, 20]! (* Vaclav Kotesovec, Jan 22 2015 *)

CROSSREFS

Twice the absolute values are in A052864.

Sequence in context: A083430 A005011 A187814 * A184140 A094869 A178824

Adjacent sequences:  A009119 A009120 A009121 * A009123 A009124 A009125

KEYWORD

sign,easy

AUTHOR

R. H. Hardin

EXTENSIONS

Extended with signs by Olivier Gérard, Mar 15 1997

STATUS

approved

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Last modified February 24 11:12 EST 2018. Contains 299603 sequences. (Running on oeis4.)