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A012861

Numerator of the coefficient of [x^(2n)] of the Taylor series log(cosec(x)*arctanh(x)).

1, 3, 4, 203, 2038, 319561, 61425307, 8552625673, 11620410478, 16155306808034, 1810024463827637, 147005475101499533, 139995370486066058107, 7441717839455761431719, 66171433716055691335387, 406949946622639944716921263, 243445385162356116120074562826

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OFFSET

1,2

COMMENTS

The inner function is cosec(x)*arctanh(x) = 1 + x^2/2 + 11*x^4/40 + 133*x^6/720 + 36211*x^8/259200 + 1226971*x^10/10886400 + ...

LINKS

Table of n, a(n) for n=1..17.

EXAMPLE

x^2/2 + 3*x^4/20 + 4*x^6/45 + 203*x^8/3240 + 2038*x^10/42525 + ...

CROSSREFS

Cf. A202602 (denominators).

Sequence in context: A042081 A245456 A042275 * A393153 A349885 A042485

Adjacent sequences: A012858 A012859 A012860 * A012862 A012863 A012864

KEYWORD

nonn,frac

AUTHOR

Patrick Demichel

EXTENSIONS

Values replaced by numerators by R. J. Mathar, Dec 20 2011

More terms from Jason Yuen, Sep 28 2025

STATUS

approved

URL: https://oeis.org/A012861

⇱ A012861 - OEIS