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Search: id:A063525
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| A063525 |
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Sum divides product: number of ordered triples of positive solutions (r,s,t) to the equation rst = n(r+s+t). |
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+0
2
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| 6, 15, 28, 30, 48, 45, 45, 78, 75, 54, 84, 94, 48, 105, 132, 105, 84, 99, 78, 189, 138, 60, 111, 210, 90, 132, 184, 129, 114, 153, 102, 228, 141, 105, 294, 267, 48, 132, 234, 228, 132, 159, 78, 300, 270, 96, 159, 301, 144, 231, 228, 162, 120, 297, 270, 429, 144, 72
(list; graph; listen)
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OFFSET
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1,1
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REFERENCES
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M. J. Pelling, "The Sum Divides the Product", Problem 10745, Amer. Math. Monthly, vol. 106 (1999), p. 587; vol. 108, (no. 7, Aug. 2001), pp. 668-669. [Gives upper bound]
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EXAMPLE
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The ordered solutions (r,s,t) of rst = 3(r+s+t) are (1,4,15), (1,5,9), (1,6,7), (2,2,12), (2,3,5), (3,3,3) for a total of 28 permuted solutions, hence a(3) = 28.
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CROSSREFS
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Cf. A063520.
Sequence in context: A112150 A072257 A140091 this_sequence A117519 A091012 A058008
Adjacent sequences: A063522 A063523 A063524 this_sequence A063526 A063527 A063528
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KEYWORD
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nonn
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AUTHOR
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Jud McCranie (j.mccranie(AT)comcast.net) Aug 01 2001
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EXTENSIONS
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More terms from David W. Wilson (davidwwilson(AT)comcast.net), Aug 01, 2001
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