OFFSET
0,3
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 0..100
MATHEMATICA
Numerator[Take[CoefficientList[Series[Sech[Csc[x] - Coth[x]], {x, 0, 35}], x], {1, -2, 2}]] (* Vincenzo Librandi, Nov 12 2016 *)
CROSSREFS
KEYWORD
sign,frac
AUTHOR
Patrick Demichel (patrick.demichel(AT)hp.com)
EXTENSIONS
Name edited by R. J. Mathar, Dec 21 2011
STATUS
approved