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Search: id:A138664
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| A138664 |
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a(n) = number of positive integers k, k <= n, where the number of one's in the binary representation of each k divides n. |
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+0
2
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| 1, 2, 2, 4, 3, 6, 3, 7, 5, 9, 4, 12, 4, 10, 8, 12, 5, 18, 5, 15, 11, 14, 5, 24, 5, 15, 14, 18, 5, 25, 5, 21
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OFFSET
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1,2
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EXAMPLE
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The integers 1 through 9 in binary are (1, 10, 11, 100, 101, 110, 111, 1000, 1001). So, the numbers of 1's in these binary representations form the sequence (1,1,2,1,2,2,3,1,2) (the first 9 terms of sequence A000120, starting from A000120(1)). 9 is divisible by all the 1's (there are 4 of those) and the one 3. So a(9) = 4+1 = 5.
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CROSSREFS
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Cf. A138663, A000120.
Sequence in context: A089173 A126090 A058266 this_sequence A140357 A089265 A113885
Adjacent sequences: A138661 A138662 A138663 this_sequence A138665 A138666 A138667
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KEYWORD
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more,nonn
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AUTHOR
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Leroy Quet (qq-quet(AT)mindspring.com), Mar 25 2008
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