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A009809
Expansion of tanh(tan(x))*cos(x).
0
1, -3, -3, 49, 2905, 83589, -334059, -351159815, -39776495567, -2339943411315, 181395497796525, 87834301596283969, 15443686178950893193, 532878946672338704661, -705534269899082168140347
OFFSET
0,2
MATHEMATICA
With[{nn=30}, Take[CoefficientList[Series[Tanh[Tan[x]]*Cos[x] , {x, 0, nn}], x] Range[ 0, nn-1]!, {2, -1, 2}]] (* Harvey P. Dale, Jan 15 2023 *)
CROSSREFS
Sequence in context: A083391 A165636 A142469 * A265717 A292753 A268136
KEYWORD
sign
AUTHOR
EXTENSIONS
Extended with signs by Olivier Gérard, Mar 15 1997
Prior Mathematica program removed by Harvey P. Dale, Jan 15 2023
STATUS
approved