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A100826
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a(1) = 1; a(n+1) = GCD(n,a(n))-th smallest positive integer not already in the sequence.
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2
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1, 2, 4, 3, 5, 10, 7, 14, 8, 6, 11, 22, 12, 9, 13, 15, 16, 17, 18, 19, 20, 21, 23, 46, 25, 50, 26, 24, 30, 27, 31, 62, 29, 28, 33, 32, 37, 74, 35, 34, 38, 36, 44, 39, 40, 47, 41, 42, 52, 43, 45, 51, 48, 49, 53, 54, 56, 55, 57, 58, 60, 59, 61, 63, 64, 65, 66, 67, 68, 69, 70, 71
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,2
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COMMENTS
| Probably a permutation of the positive integers.
This is a permutation iff, infinitely often, gcd(n, a(n)) = 1. Through n = 1000, gcd(n, a(n)) = 1 612 times, which is consistent with the natural conjecture that this is true with density 6/Pi^2 ~ .6079.... - Franklin T. Adams-Watters (FrankTAW(AT)Netscape.net), Nov 28 2006
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LINKS
| Franklin T. Adams-Watters, Table of n, a(n) for n = 1..1000
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MATHEMATICA
| a[1] = 1; a[n_] := a[n] = Complement[ Range[250], Table[a[i], {i, n - 1}]][[GCD[n - 1, a[n - 1]]]]; Table[ a[n], {n, 60}] (from Robert G. Wilson v Jan 10 2005)
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CROSSREFS
| Cf. A125628.
Sequence in context: A072799 A091449 A100834 * A093416 A073944 A072937
Adjacent sequences: A100823 A100824 A100825 * A100827 A100828 A100829
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KEYWORD
| nonn
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AUTHOR
| Leroy Quet Jan 06 2005
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EXTENSIONS
| More terms from Robert G. Wilson v (rgwv(AT)rgwv.com), Jan 10 2005
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