

A013541


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


2



1, 1, 217, 214279, 824071, 337533513773, 8320611986431, 2303253020856673, 7111553692366818727, 4825610634542923917792887, 6031202702741413913839327, 1707209475196496091030335944673
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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: A086026 A100794 A048258 * A167912 A038662 A121379
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



