A013541 Numerator of the coefficient [x^(2n)] of the Taylor series cos(cosec(x) - coth(x)).

1, -1, 217, -214279, 824071, -337533513773, 8320611986431, -2303253020856673, 7111553692366818727, -4825610634542923917792887, 6031202702741413913839327, -1707209475196496091030335944673

Offset

0,3

Comments

Most (but not all) denominators are in the bisection of A202382.

Links

G. C. Greubel, Table of n, a(n) for n = 0..194

Example

1 - x^2/72 + 217*x^4/31104 - 214279*x^6/235146240 + 824071*x^8/9674588160 - ...

Mathematica

Numerator[Take[CoefficientList[Series[Cos[Csc[x] - Coth[x]], {x, 0, 26}], x], {1, -1, 2}]] (* G. C. Greubel, Nov 13 2016 *)

Crossrefs

Sequence in context: A100794 A048258 A373762 * A352468 A167912 A038662

Adjacent sequences: A013538 A013539 A013540 * A013542 A013543 A013544

Keyword

sign,frac

Author

Patrick Demichel (patrick.demichel(AT)hp.com)

Extensions

Name edited by R. J. Mathar, Dec 21 2011

Status

approved