OFFSET
0,2
MATHEMATICA
With[{nn=40}, Take[CoefficientList[Series[Sech[Tanh[x]Tan[x]], {x, 0, nn}], x] Range[0, nn]!, {1, -2, 4}]] (* Harvey P. Dale, Sep 10 2019 *)
CROSSREFS
KEYWORD
sign
AUTHOR
Patrick Demichel (patrick.demichel(AT)hp.com)
EXTENSIONS
More terms from Harvey P. Dale, Sep 10 2019
STATUS
approved