A013547 Numerator of the coefficient [x^(2n)] of the Taylor expansion sec(cosec(x)-coth(x))= 1+x^2/72 -211*x^4/31104 +169339*x^6/235146240 -205787*x^8/13544423424+...

1, 1, -211, 169339, -205787, 124654123973, 4233334384067, 458968419865477, 460700758945363763, 1003433160159825045756551, 1160527066076017343605453327, 537107192671326620106145350461, 11100661279966114788004381836713, 90437772951214017777023420366691881

Offset

0,3

Comments

The associated denominators are generally (but not always) in the bisection of A202382.

Links

Vincenzo Librandi, Table of n, a(n) for n = 0..100

Mathematica

Numerator[Take[CoefficientList[Series[Sec[Csc[x] - Coth[x]], {x, 0, 35}], x], {1, -2, 2}]] (* Vincenzo Librandi, Nov 12 2016 *)

Crossrefs

Sequence in context: A116075 A276462 A096834 * A181002 A323426 A099687

Adjacent sequences: A013544 A013545 A013546 * A013548 A013549 A013550

Keyword

sign,frac

Author

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

Extensions

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

Status

approved