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A145613 Numerator of the polynomial A_l(x) = sum_{d=1..l-1} x^(l-d)/d for index l=2n+1 evaluated at x=3. 2
21, 393, 17731, 2234571, 20111503, 1991042087, 33278851497, 119803867191, 54989975121893, 15672142912044093, 987345003473390379, 204380415719298965303, 9197118707369867504211, 248322205098990353297597 (list; graph; refs; listen; history; internal format)
OFFSET

1,1

COMMENTS

For denominators see A145614. For general properties of A_l(x) see A145609.

MAPLE

A := proc(l, x) add(x^(l-d)/d, d=1..l-1) ; end: A145613 := proc(n) numer( A(2*n+1, 3)) ; end: seq(A145613(n), n=1..20) ; # R. J. Mathar, Aug 21 2009

MATHEMATICA

m = 3; aa = {}; Do[k = 0; Do[k = k + m^(2 r + 1 - d)/d, {d, 1, 2 r}]; AppendTo[aa, Numerator[k]], {r, 1, 25}]; aa (*Artur Jasinski*)

CROSSREFS

Cf. A145609 - A145640.

Sequence in context: A001881 A108740 A094172 * A015677 A113363 A014903

Adjacent sequences:  A145610 A145611 A145612 * A145614 A145615 A145616

KEYWORD

frac,nonn

AUTHOR

Artur Jasinski (grafix(AT)csl.pl), Oct 14 2008

EXTENSIONS

Edited by R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Aug 21 2009

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Last modified February 14 23:44 EST 2012. Contains 205689 sequences.