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A009309
Expansion of log(1+log(1+sinh(x))).
0
0, 1, -2, 8, -43, 299, -2566, 26200, -310458, 4190709, -63507976, 1067945504, -19737313696, 397714143007, -8678720911680, 203901057411888, -5131882643803216, 137757901532413673, -3928752297641273728
OFFSET
0,3
FORMULA
a(n) ~ (n-1)! * (-1)^(n+1) / (arcsinh(1-exp(-1)))^n. - Vaclav Kotesovec, Jan 22 2015
MATHEMATICA
Log[ 1+Log[ 1+Sinh[ x ] ] ]
CoefficientList[Series[Log[1 + Log[1 + Sinh[x]]], {x, 0, 20}], x] * Range[0, 20]! (* Vaclav Kotesovec, Jan 22 2015 *)
CROSSREFS
Sequence in context: A326561 A007169 A106327 * A276497 A324670 A334335
KEYWORD
sign,easy
AUTHOR
EXTENSIONS
Extended with signs by Olivier Gérard, Mar 15 1997
STATUS
approved