A068557 From denominators in expansion of tan(arcsinh(x)) - sin(arctanh(x)).

1, 1, 1, 1, 189, 189, 12474, 43659, 4191264, 37721376, 120406632192, 220745492352, 974812094226432, 78959779632340992, 4421747659411095552, 1658155372279160832, 49948354512933617664, 1519878479474057051897856, 15633035788876015390949376

Offset

0,5

References

R. W. Gosper, personal communication, Mar 07, 2002

Links

Table of n, a(n) for n=0..18.

Example

4/189*x^9+4/189*x^11+377/12474*x^13+1202/43659*x^15+...

Mathematica

Take[Denominator[CoefficientList[Series[Tan[ArcSinh[x]]-Sin[ArcTanh[x]], {x, 0, 40}], x]], {2, -1, 2}] (* Harvey P. Dale, Dec 17 2014 *)

Crossrefs

Cf. A068556.

Sequence in context: A035832 A065612 A088264 * A253024 A031901 A348160

Adjacent sequences: A068554 A068555 A068556 * A068558 A068559 A068560

Keyword

nonn,frac

Author

N. J. A. Sloane, Mar 23 2002

Status

approved