OFFSET
0,5
FORMULA
a(n) ~ n! * (-1)^(n+1) / ((exp(Pi/2)-1) * cosh(1-exp(-Pi/2)) * (1-exp(-Pi/2))^n). - Vaclav Kotesovec, Jan 23 2015
MATHEMATICA
Tan[ Log[ 1+x ] ]/Cosh[ x ]
CoefficientList[Series[Sech[x]*Tan[Log[1 + x]], {x, 0, 20}], x] * Range[0, 20]! (* Vaclav Kotesovec, Jan 23 2015 *)
CROSSREFS
KEYWORD
sign,easy
AUTHOR
EXTENSIONS
Extended with signs by Olivier Gérard, Mar 15 1997
STATUS
approved