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A102065
Denominators of e.g.f.: -cot(arctanh(x)), odd powers only.
2
3, 3, 63, 9, 11, 63, 63, 9, 3591, 693, 2277, 189, 189, 21, 7161, 77, 21, 3591, 171, 99, 625779, 47817, 68103, 1323, 297, 297, 16929, 171, 531, 64449
OFFSET
1,1
EXAMPLE
cot(arctanh(x)) = 1/x - (2/3)*x - (4/3)*x^3/3! - (1040/63)*x^5/5! - ...
MATHEMATICA
With[{nn=60}, Take[CoefficientList[Series[-Cot[ArcTanh[x]], {x, 0, nn}], x] Range[ 0, nn-1]!, {2, -1, 2}]]//Quiet//Denominator (* Harvey P. Dale, Sep 26 2020 *)
CROSSREFS
Numerators are in A102064.
Sequence in context: A165497 A051752 A332786 * A102074 A126227 A333827
KEYWORD
nonn,frac
AUTHOR
Ralf Stephan, Dec 28 2004
STATUS
approved