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Search: id:A066572
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| A066572 |
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Number of sets of distinct positive integers with geometric mean n. |
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+0
3
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| 1, 3, 3, 9, 3, 255, 3, 31, 9, 255, 3, 48891, 3, 255, 255, 117, 3, 48891, 3, 48891, 255, 255, 3, 12896331, 9, 255, 31, 48891, 3, 329166915027, 3, 479, 255, 255, 255, 668187863, 3, 255, 255, 12896331, 3, 329166915027, 3, 48891, 48891, 255, 3, 3981060137, 9, 48891, 255, 48891, 3
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OFFSET
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1,2
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COMMENT
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a(m) = a(n) if m and n have the same factorization structure.
a(60) is approximately 9.3492e20. - Frank Adams-Watters (FrankTAW(AT)Netscape.net), Jun 09 2006
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EXAMPLE
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a(2) = 3 as there are three sets viz. {2), {1,4), {1,2,4}, the geometric mean of whose elements is 2.
a(4) = 9: the nine sets are {4}, {1, 16}, {2, 8}, {1, 4, 16}, {2, 4, 8}, {1, 2, 32}, {1, 2, 4, 32}, {1, 2, 8, 16}, {1, 2, 4, 8, 16}.
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CROSSREFS
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Cf. A066571.
Sequence in context: A157031 A113213 A088032 this_sequence A104195 A062131 A124871
Adjacent sequences: A066569 A066570 A066571 this_sequence A066573 A066574 A066575
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KEYWORD
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nonn,nice
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AUTHOR
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Amarnath Murthy (amarnath_murthy(AT)yahoo.com), Dec 19 2001
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EXTENSIONS
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More terms from Naohiro Nomoto (n_nomoto(AT)yabumi.com), Dec 26 2001
More terms from Frank Adams-Watters (FrankTAW(AT)Netscape.net), Jun 09 2006
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