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A102064
Numerators of e.g.f.: -cot(arctanh(x)), odd powers only.
1
2, 4, 1040, 4640, 331520, 178470400, 24593254400, 666964480000, 66553013755904000, 4091041782710272000, 5311565147410595840000, 211592629697932820480000, 121215491006931795968000000
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=30}, Take[Numerator[CoefficientList[Series[-Cot[ArcTanh[x]], {x, 0, nn}], x] Range[0, nn-1]!], {2, -1, 2}]]//Quiet (* Harvey P. Dale, Jul 08 2017 *)
CROSSREFS
Denominators are in A102065.
Sequence in context: A009562 A045647 A219452 * A085638 A134718 A328313
KEYWORD
nonn,frac
AUTHOR
Ralf Stephan, Dec 28 2004
STATUS
approved