login
A009638
Expansion of e.g.f.: tan(log(1+sinh(x))).
0
0, 1, -1, 5, -22, 151, -1186, 11255, -121752, 1493101, -20381896, 306816905, -5045231632, 89977880851, -1729461315856, 35637607318955, -783658693590912, 18315607922069401, -453368586519154816, 11848112075773043405
OFFSET
0,4
FORMULA
a(n) ~ n! * (-1)^(n+1) / (sqrt(1-2*exp(Pi/2)+2*exp(Pi)) * log(1 - exp(-Pi/2) + sqrt(1 + (exp(-Pi/2)-1)^2))^(n+1)). - Vaclav Kotesovec, Jan 23 2015
MATHEMATICA
CoefficientList[Series[Tan[Log[1 + Sinh[x]]], {x, 0, 20}], x] * Range[0, 20]! (* Vaclav Kotesovec, Jan 23 2015 *)
CROSSREFS
Sequence in context: A372139 A028561 A227918 * A346410 A121942 A006294
KEYWORD
sign,easy
AUTHOR
EXTENSIONS
Extended with signs by Olivier Gérard, Mar 15 1997
First Mathematica program deleted and definition clarified by Harvey P. Dale, Feb 20 2023
STATUS
approved