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Search: id:A161764
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| A161764 |
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a(n) = the largest multiple of {the number of 1's in the binary representation of n} that is <= n. |
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+0
2
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| 1, 2, 2, 4, 4, 6, 6, 8, 8, 10, 9, 12, 12, 12, 12, 16, 16, 18, 18, 20, 21, 21, 20, 24, 24, 24, 24, 27, 28, 28, 30, 32, 32, 34, 33, 36, 36, 36, 36, 40, 39, 42, 40, 42, 44, 44, 45, 48, 48, 48, 48, 51, 52, 52, 55, 54, 56, 56, 55, 60, 60, 60, 60, 64, 64, 66, 66, 68, 69, 69, 68, 72, 72
(list; graph; listen)
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OFFSET
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1,2
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EXAMPLE
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11 (decimal) in binary is 1011. There are three 1's. Because 9 is the largest multiple of 3 that is <= 11, then a(11) = 9.
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MAPLE
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a := proc (n) local n2, n1, j: n2 := convert(n, base, 2): n1 := add(n2[i], i = 1 .. nops(n2)): for j while j*n1 <= n do j*n1 end do end proc: seq(a(n), n = 1 .. 80); [From Emeric Deutsch (deutsch(AT)duke.poly.edu), Jun 26 2009]
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PROGRAM
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(PARI) a(n)=local(B=binary(n), w=B*vector(#B, x, 1)~); n-n%w [From Hagen von Eitzen (math(AT)von-eitzen.de), Jun 22 2009]
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CROSSREFS
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A161765, A000120
Sequence in context: A096494 A116568 A061106 this_sequence A131055 A052928 A137501
Adjacent sequences: A161761 A161762 A161763 this_sequence A161765 A161766 A161767
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KEYWORD
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base,nonn
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AUTHOR
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Leroy Quet (q1qq2qqq3qqqq(AT)yahoo.com), Jun 18 2009
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EXTENSIONS
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Extended by Hagen von Eitzen (math(AT)von-eitzen.de) and Emeric Deutsch (deutsch(AT)duke.poly.edu), Jun 26 2009
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