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Search: id:A007409
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| A007409 |
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Denominators of Sum k^-3; k = 1..n.
(Formerly M4579)
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+0
9
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| 1, 8, 216, 1728, 216000, 24000, 8232000, 65856000, 16003008000, 16003008000, 21300003648000, 21300003648000, 46796108014656000, 46796108014656000, 46796108014656000, 374368864117248000, 1839274229408039424000
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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Largest prime factor in A007409(n) (n>1) is A007917(n), occuring always to the power 3. - M. F. Hasler (Maximilian.Hasler(AT)gmail.com), Nov 10 2006
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REFERENCES
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N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
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.
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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 (Maximilian.Hasler(AT)gmail.com), Nov 10 2006
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MATHEMATICA
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s=0; lst={}; Do[s+=n^1/n^4; AppendTo[lst, Denominator[s]], {n, 3*4!}]; lst [From Vladimir Orlovsky (4vladimir(AT)gmail.com), Jan 24 2009]
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CROSSREFS
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Cf. A007408.
Cf. A007917.
Sequence in context: A016827 A163289 A060459 this_sequence A069045 A123057 A009072
Adjacent sequences: A007406 A007407 A007408 this_sequence 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 (njas(AT)research.att.com), Mira Bernstein
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