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Search: id:A145612
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| A145612 |
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Denominator of the polynomial A_l(x) = sum_{d=1..l-1} x^(l-d)/d for index l=2n+1 evaluated at x=2. |
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+0
2
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| 1, 6, 15, 420, 63, 1386, 9009, 360360, 1531530, 29099070, 14549535, 1338557220, 1673196525, 10039179150, 145568097675, 72201776446800, 18050444111700, 9025222055850, 166966608033225, 667866432132900, 6845630929362225
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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For numerators see A145611. For general properties of A_l(x) see A145609.
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MAPLE
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A := proc(l, x) add(x^(l-d)/d, d=1..l-1) ; end: A145612 := proc(n) denom( A(2*n+1, 2)) ; end: seq(A145612(n), n=1..20) ; # R. J. Mathar, Aug 21 2009
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MATHEMATICA
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m = 2; aa = {}; Do[k = 0; Do[k = k + m^(2 r + 1 - d)/d, {d, 1, 2 r}]; AppendTo[aa, Denominator[k]], {r, 1, 30}]; aa (*Artur Jasinski*)
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CROSSREFS
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Cf. A145609 - A145640.
Sequence in context: A003155 A024081 A145558 this_sequence A068941 A107777 A136140
Adjacent sequences: A145609 A145610 A145611 this_sequence A145613 A145614 A145615
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KEYWORD
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frac,nonn
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AUTHOR
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Artur Jasinski (grafix(AT)csl.pl), Oct 14 2008
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EXTENSIONS
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Edited by R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Aug 21 2009
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