OFFSET
0,2
EXAMPLE
0/0!*x^0 + 2/2!*x^2 + 12/4!*x^4 - 98/6!*x^6 - 16968/8!*x^8 ...
MAPLE
egf := arctan(tan(x)*sinh(x)): ser := series(egf, x, 33):
seq((2*n)!*coeff(ser, x, 2*n), n = 0..15); # Peter Luschny, Apr 23 2024
MATHEMATICA
With[{nn=30}, Take[CoefficientList[Series[ArcTan[Sinh[x]Tan[x]], {x, 0, nn}], x] Range[0, nn]!, {1, -1, 2}]] (* Harvey P. Dale, Oct 17 2015 *)
CROSSREFS
KEYWORD
sign
AUTHOR
Patrick Demichel (patrick.demichel(AT)hp.com)
EXTENSIONS
Missing a(0) = 0 prepended and new name by Peter Luschny, Apr 23 2024
STATUS
approved