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Search: id:A145610
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| A145610 |
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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=1. |
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+0
2
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| 2, 12, 20, 280, 2520, 27720, 360360, 720720, 4084080, 15519504, 5173168, 356948592, 8923714800, 80313433200, 2329089562800, 144403552893600, 13127595717600, 13127595717600, 485721041551200, 485721041551200
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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For numerators and explicit examples of the polynomials 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: A145610 := proc(n) denom( A(2*n+1, 1)) ; end: seq(A145610(n), n=1..20) ; # R. J. Mathar, Aug 21 2009
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MATHEMATICA
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m = 1; 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: A121859 A145622 A145634 this_sequence A096108 A098941 A031001
Adjacent sequences: A145607 A145608 A145609 this_sequence A145611 A145612 A145613
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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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