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A007409
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Denominators of Sum k^-3; k = 1..n.
(Formerly M4579)
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9
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1, 8, 216, 1728, 216000, 24000, 8232000, 65856000, 16003008000, 16003008000, 21300003648000, 21300003648000, 46796108014656000, 46796108014656000, 46796108014656000, 374368864117248000, 1839274229408039424000
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OFFSET
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1,2
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COMMENTS
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Largest prime factor in A007409(n) (n > 1) is A007917(n), occurring always to the power 3. - M. F. Hasler, Nov 10 2006
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REFERENCES
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D. Y. Savio, E. A. Lamagna and S.-M. Liu, Summation of harmonic numbers, pp. 12-20 of E. Kaltofen and S. M. Watt, editors, Computers and Mathematics, Springer-Verlag, NY, 1989.
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
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LINKS
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T. D. Noe, Table of n, a(n) for n=1..200
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MAPLE
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A007409:= n->denom(sum(1/k^3, k=1..n)); # M. F. Hasler, Nov 10 2006
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MATHEMATICA
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Table[Denominator[Sum[1/k^3, {k, n}]], {n, 10}] (* Alonso del Arte, Dec 30 2012 *)
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CROSSREFS
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Cf. A007408.
Cf. A007917.
Sequence in context: A016827 A163289 A060459 * A195506 A069045 A123057
Adjacent sequences: A007406 A007407 A007408 * A007410 A007411 A007412
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KEYWORD
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nonn,frac
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AUTHOR
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N. J. A. Sloane, Mira Bernstein
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STATUS
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approved
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