A013557 Numerator of [x^(2n)] of the Taylor series sec(cot(x)-coth(x))= 1 +2*x^2/9 +10*x^4/243 +2356*x^6/229635 +986*x^8/413343+...

1, 2, 10, 2356, 986, 36236852, 45967324, 6310668536, 55999847998, 13505508015664052, 73561146096203972, 1018280445612115249048, 184320514834002228148, 30993244629183109104307016

Offset

0,2

Links

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

Mathematica

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

Crossrefs

Sequence in context: A334575 A000884 A328157 * A007158 A155733 A080485

Adjacent sequences: A013554 A013555 A013556 * A013558 A013559 A013560

Keyword

nonn,frac

Author

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

Extensions

Name edited by R. J. Mathar, Dec 22 2011

Status

approved