OFFSET
0,3
FORMULA
a(n) ~ n! * cosh(1-exp(-Pi/2)) / ((exp(Pi/2)-1) * (exp(-Pi/2)-1)^n). - Vaclav Kotesovec, Jan 22 2015
MATHEMATICA
Cosh[ x ]/Cos[ Log[ 1+x ] ]
CoefficientList[Series[Cosh[x]*Sec[Log[1 + x]], {x, 0, 20}], x] * Range[0, 20]! (* Vaclav Kotesovec, Jan 22 2015 *)
CROSSREFS
KEYWORD
sign,easy
AUTHOR
EXTENSIONS
Extended with signs by Olivier Gérard, Mar 15 1997
STATUS
approved