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A009839
Expansion of e.g.f.: tanh(x)/cos(log(1+x)).
1
0, 1, 0, 1, -12, 76, -480, 4264, -45248, 514180, -6418080, 89205348, -1356339600, 22268993280, -393425899776, 7452539807088, -150601672807680, 3232773233449104, -73469416841374464, 1762493272462111632
OFFSET
0,5
LINKS
FORMULA
a(n) ~ n! * (-1)^(n+1) * tanh(1-exp(-Pi/2)) / ((exp(Pi/2)-1) * (1-exp(-Pi/2))^n). - Vaclav Kotesovec, Jan 24 2015
MATHEMATICA
With[{nn=20}, CoefficientList[Series[Tanh[x]/Cos[Log[1+x]], {x, 0, nn}], x] Range[0, nn]!] (* Harvey P. Dale, Aug 07 2013 *)
CROSSREFS
Sequence in context: A044580 A075279 A009405 * A190066 A335253 A071767
KEYWORD
sign,easy
AUTHOR
EXTENSIONS
Extended with signs by Olivier Gérard, Mar 15 1997
Definition clarified and prior Mathematica program replaced by Harvey P. Dale, Aug 07 2013
STATUS
approved