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A013519 Numerator of [x^(2n+1)] in the Taylor expansion tan(cosec(x)-cot(x)). 1
1, 1, 3, 181, 59, 3455, 3332389, 173339393, 449509681, 198232237033, 1032475444411, 101635950910031, 71432133543444211, 671713726985602398481 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

COMMENTS

The e.g.f. of x/2, tan(cosec(x)-cot(x)) = x/(2^1*1!) + 4*x^3/(2^3*3!) +72*x^5/(2^5*5!) + 2896*x^7/(2^7*7!) +.. is apparently covered by A003718.

LINKS

G. C. Greubel, Table of n, a(n) for n = 0..125

EXAMPLE

x/2 +x^3/12 +3*x^5/160 +181*x^7/40320 +59*x^9/53760 +3455*x^11/12773376 +...

MATHEMATICA

Numerator[Take[CoefficientList[Series[Tan[Csc[x] - Cot[x]], {x, 0, 25}], x], {2, -1, 2}]] (* G. C. Greubel, Nov 12 2016 *)

CROSSREFS

Sequence in context: A270245 A093434 A053291 * A042779 A103503 A203562

Adjacent sequences:  A013516 A013517 A013518 * A013520 A013521 A013522

KEYWORD

nonn,frac

AUTHOR

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

EXTENSIONS

Name edited by R. J. Mathar, Dec 19 2011

STATUS

approved

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Last modified November 23 20:23 EST 2017. Contains 295141 sequences.