OFFSET
0,4
FORMULA
a(n) ~ (n-1)! * (-1)^(n+1) * exp(-Pi/4) * (4/Pi)^n. - Vaclav Kotesovec, Jan 23 2015
MATHEMATICA
Log[ 1+Tan[ x ] ]*Exp[ x ]
CoefficientList[Series[E^x*Log[1 + Tan[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