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Search: id:A036764
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| A036764 |
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If n can be expressed as m/d(m) for some m, where d(m) is the number of divisors of m (A000005), then a(n) is the smallest such m, otherwise a(n) = 0. |
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+0
1
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| 1, 8, 9, 36, 40, 72, 56, 80, 108, 180, 88, 240, 104, 252, 360, 128, 136, 0, 152, 480, 504, 396, 184, 384, 225, 468, 0, 560, 232, 0, 248, 448, 792, 612, 1260, 864, 296, 684, 936, 640, 328, 1680, 344, 880, 0, 828, 376, 1152, 441, 1800, 1224, 1040, 424, 972, 1980, 896, 1368
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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If a(n) = q (say) is not zero, then x=q*d[x] has only a finite number of solutions. See A036763 for the numbers which cannot be expressible as m/d(m) for some m.
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EXAMPLE
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If q=25 then 25*9=225, 25*18=450 and 25*24=600 so that d[ 225 ],d[ 450 ],d[ 600 ] are 9,18,24 resp. The smallest is 225. Thus a[25]=225.
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CROSSREFS
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Cf. A000005, A033950, A036761-A036763.
Adjacent sequences: A036761 A036762 A036763 this_sequence A036765 A036766 A036767
Sequence in context: A120776 A041136 A041915 this_sequence A129548 A075079 A041933
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KEYWORD
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nonn
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AUTHOR
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Labos E. (labos(AT)ana.sote.hu)
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EXTENSIONS
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Additional comments from Asher Auel (asher.auel(AT)reed.edu), May 17 2001
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