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Search: id:A140965
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| A140965 |
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Smallest multiple of n with a number of divisors >= n. |
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+0
1
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| 1, 2, 6, 8, 20, 12, 42, 24, 36, 60, 132, 60, 312, 168, 120, 240, 612, 180, 912, 240, 420, 660, 1380, 360, 900, 1560, 1080, 840, 3480, 720, 3720, 1440, 1980, 3060, 1260, 1260, 8880, 4560, 3120, 1680, 14760, 2520, 15480, 3960, 2520, 8280, 16920, 3360, 8820
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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Also add a(n)/n as a separate sequence; first 8 terms are 1,1,2,2,4,2,6,3
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EXAMPLE
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a(8) = 24 because 8 has only 4 divisors and 16 has only 5, but 24 has 8 and so 24 qualifies.
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MATHEMATICA
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a = {}; For[n = 1, n < 50, n++, i = 1; While[DivisorSigma[0, i*n] < n, i++ ]; AppendTo[a, n*i]]; a [From Stefan Steinerberger (stefan.steinerberger(AT)gmail.com), Aug 28 2008]
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CROSSREFS
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Adjacent sequences: A140962 A140963 A140964 this_sequence A140966 A140967 A140968
Sequence in context: A072230 A028332 A124827 this_sequence A002618 A069553 A143481
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KEYWORD
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nonn
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AUTHOR
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J. Lowell (jhbubby(AT)mindspring.com), Jul 27 2008
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EXTENSIONS
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More terms from Stefan Steinerberger (stefan.steinerberger(AT)gmail.com), Aug 28 2008
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