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A009431
Expansion of log(1+x)/cosh(sin(x)).
1
0, 1, -1, -1, 0, 49, -165, -393, -504, 70785, -434385, -517265, -12647976, 654552625, -6276987717, 18362076327, -636272644560, 22683808563841, -312594994151361, 2817355930176479, -72112751626318640, 2222078368780722865
OFFSET
0,6
FORMULA
a(n) ~ (n-1)! * (-1)^(n+1) / cosh(sin(1)). - Vaclav Kotesovec, Jan 23 2015
MATHEMATICA
Log[ 1+x ]/Cosh[ Sin[ x ] ]
CoefficientList[Series[Log[1 + x]*Sech[Sin[x]], {x, 0, 20}], x] * Range[0, 20]! (* Vaclav Kotesovec, Jan 23 2015 *)
CROSSREFS
Sequence in context: A066551 A134210 A009409 * A226353 A074216 A216870
KEYWORD
sign,easy
AUTHOR
EXTENSIONS
Extended with signs by Olivier Gérard, Mar 15 1997
STATUS
approved