OFFSET
0,3
COMMENTS
The e.g.f. of x/2, tan(cosec(x)-cot(x)) = x/(2^1*1!) + 4*x^3/(2^3*3!) +72*x^5/(2^5*5!) + 2896*x^7/(2^7*7!) +.. is apparently covered by A003718.
LINKS
G. C. Greubel, Table of n, a(n) for n = 0..125
EXAMPLE
x/2 +x^3/12 +3*x^5/160 +181*x^7/40320 +59*x^9/53760 +3455*x^11/12773376 +...
MATHEMATICA
Numerator[Take[CoefficientList[Series[Tan[Csc[x] - Cot[x]], {x, 0, 25}], x], {2, -1, 2}]] (* G. C. Greubel, Nov 12 2016 *)
CROSSREFS
KEYWORD
nonn,frac
AUTHOR
Patrick Demichel (patric.demichel(AT)hp.com)
EXTENSIONS
Name edited by R. J. Mathar, Dec 19 2011
STATUS
approved