OFFSET
0,4
FORMULA
a(n) ~ (n-1)! * (-1)^(n+1) * (exp(-Pi/4) + exp(Pi/4)) * 2^(2*n-1) / Pi^n. - Vaclav Kotesovec, Jan 23 2015
MATHEMATICA
With[{nn=20}, CoefficientList[Series[Log[1+Tan[x]]*Cosh[x], {x, 0, nn}], x] Range[0, nn]!] (* Harvey P. Dale, May 25 2013 *)
CROSSREFS
KEYWORD
sign,easy
AUTHOR
EXTENSIONS
Extended with signs by Olivier Gérard, Mar 15 1997
STATUS
approved