OFFSET
0,4
FORMULA
a(n) ~ (n-1)! * (-1)^(n+1) / cos(sinh(1)). - Vaclav Kotesovec, Jan 24 2015
MATHEMATICA
Log[ 1+x ]/Cos[ Sinh[ x ] ]
CoefficientList[Series[Log[1 + x]*Sec[Sinh[x]], {x, 0, 20}], x] * Range[0, 20]! (* Vaclav Kotesovec, Jan 24 2015 *)
CROSSREFS
KEYWORD
sign,easy
AUTHOR
EXTENSIONS
Extended with signs by Olivier Gérard, Mar 15 1997
STATUS
approved