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A035047 Denominators of alternating sum transform (PSumSIGN) of Harmonic numbers H(n) = A001008/A002805. 2
1, 2, 3, 4, 15, 12, 105, 24, 315, 120, 3465, 40, 45045, 280, 45045, 560, 765765, 5040, 14549535, 5040, 14549535, 55440, 334639305, 55440, 1673196525, 720720, 5019589575, 720720, 145568097675, 720720 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Robert Israel, Table of n, a(n) for n = 1..2000

N. J. A. Sloane, Transforms

FORMULA

G.f. for A035048(n)/A035047(n) : log(1-x)/(x^2-1). - Benoit Cloitre, Jun 15 2003

a(n) = denominator((-1)^(n+1)*1/2*(log(2)+(-1)^(n+1)*(gamma+1/2*(psi(1+n/2)-psi(3/2+n/2))+psi(2+n)))), with gamma the Euler-Mascheroni constant. - [Gerry Martens, Apr 28 2011]

MAPLE

S:= series(log(1-x)/(x^2-1), x, 101):

seq(denom(coeff(S, x, j)), j=1..100); # Robert Israel, Jun 02 2015

PROG

(PARI) a(n)=denominator(polcoeff(log(1-x)/(x^2-1)+O(x^(n+1)), n))

CROSSREFS

Cf. A035048.

Sequence in context: A204983 A249623 A251637 * A037323 A065812 A081350

Adjacent sequences:  A035044 A035045 A035046 * A035048 A035049 A035050

KEYWORD

nonn,frac,easy

AUTHOR

N. J. A. Sloane.

STATUS

approved

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Last modified May 22 05:57 EDT 2019. Contains 323474 sequences. (Running on oeis4.)