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Search: id:A143146
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| A143146 |
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a(n) = the smallest positive multiple of n that has the same number of 0's as 1's in its binary representation. |
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+0
2
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| 2, 2, 9, 12, 10, 12, 35, 56, 9, 10, 44, 12, 52, 42, 135, 240, 153, 180, 38, 180, 42, 44, 184, 216, 50, 52, 135, 56, 232, 150, 527, 992, 165, 170, 35, 180, 37, 38, 156, 240, 41, 42, 172, 44, 135, 184, 141, 240, 49, 50, 153, 52, 212, 216, 165, 56, 228, 232, 177, 180
(list; graph; listen)
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OFFSET
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1,1
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LINKS
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Leroy Quet, Home Page (listed in lieu of email address)
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EXAMPLE
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For n = 7, checking: 7*1 = 7 = 111 in binary; 7*2 = 14 = 1110 in binary; 7*3 = 21 = 10101 in binary; 7*4 = 28 = 11100. All of these have two many 1's in binary. But 7*5 = 35 = 100011 in binary, which has both three 0's and three 1's. So a(7) = 35.
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MAPLE
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a:=proc(n) local b, k: b:=proc(m) convert(m, base, 2) end proc: for k while add(b(k*n)[j], j=1..nops(b(k*n))) <> nops(b(k*n))-add(b(k*n)[j], j=1..nops(b(k*n))) do end do: k*n end proc: seq(a(n), n=1..60); [From Emeric Deutsch (deutsch(AT)duke.poly.edu), Aug 16 2008]
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CROSSREFS
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Cf. A031443, A143147.
Sequence in context: A154100 A002880 A066324 this_sequence A039796 A007024 A019223
Adjacent sequences: A143143 A143144 A143145 this_sequence A143147 A143148 A143149
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KEYWORD
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base,nonn
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AUTHOR
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Leroy Quet Jul 27 2008
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EXTENSIONS
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More terms from Emeric Deutsch (deutsch(AT)duke.poly.edu), Aug 16 2008
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