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Search: id:A115510
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| A115510 |
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a(1)=1. a(n) is smallest positive integer not occurring earlier in the sequence such that a(n) and a(n-1) have at least one 1-bit in the same position when they are written in binary. |
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+0
2
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| 1, 3, 2, 6, 4, 5, 7, 9, 8, 10, 11, 12, 13, 14, 15, 17, 16, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 33, 32, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 65, 64, 66, 67, 68, 69, 70, 71, 72
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OFFSET
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1,2
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COMMENT
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Sequence is a permutation of the positive integers. A115511 is the inverse permutation.
(4,6,5) is a 3-cycle and (2^k,2^k+1) for k = 1 and k > 2 are 2-cycles; all other numbers are fixed points. (Klaus Brockhaus)
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EXAMPLE
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a(3) = 2 = 10 in binary. Among the positive integers not occurring among the first 3 terms of the sequence (4 = 100 in binary, 5 = 101 in binary, 6 = 110 in binary,...), 6 is the smallest that shares at least one 1-bit with a(3) when written in binary. So a(4) = 6.
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CROSSREFS
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Cf. A109812, A115511.
Sequence in context: A121647 A033940 A106409 this_sequence A070264 A084494 A084498
Adjacent sequences: A115507 A115508 A115509 this_sequence A115511 A115512 A115513
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KEYWORD
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easy,nonn
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AUTHOR
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Leroy Quet (qq-quet(AT)mindspring.com), Jan 23 2006
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EXTENSIONS
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More terms from Klaus Brockhaus (klaus-brockhaus(AT)t-online.de), Jan 24 2006
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