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A013550 Numerator of the coefficient of [x^n] in the Taylor expansion exp(cot(x) - cosech(x)). 1
1, -1, 1, -55, 217, -4219, 214279, -802171, 824071, -109684277, 337533513773, -760100160121, 8320611986431, -265779449377027, 2303253020856673, -417652078505070229, 7111553692366818727, -7396136516120375032117 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,4

COMMENTS

The inner function is cot(x) - cosech(x) = -x/6 - x^3/24 - x^5/15120 - 17*x^7/40320 - x^9/23950080 - 691*x^11/159667200 - ...

LINKS

G. C. Greubel, Table of n, a(n) for n = 0..388

FORMULA

1 - x/6 + x^2/72 - 55*x^3/1296 + 217*x^4/31104 - 4219*x^5/6531840 + ...

MATHEMATICA

Numerator[Take[CoefficientList[Series[Exp[Cot[x] - Csch[x]], {x, 0, 40}], x], {1, -1, 1}]] (* G. C. Greubel, Nov 13 2016 *)

CROSSREFS

Cf. A013537, A013541 (bisections?).

Sequence in context: A105442 A158646 A294461 * A254148 A271738 A280888

Adjacent sequences:  A013547 A013548 A013549 * A013551 A013552 A013553

KEYWORD

sign,frac

AUTHOR

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

EXTENSIONS

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

STATUS

approved

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Last modified November 21 16:08 EST 2017. Contains 295003 sequences.