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Search: id:A126917
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| A126917 |
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a(1)=1. a(n) = the (largest proper divisor of n)th integer from among those positive integers not occurring earlier in the sequence. |
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+0
2
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| 1, 2, 3, 5, 4, 8, 6, 11, 10, 14, 7, 17, 9, 20, 18, 23, 12, 26, 13, 29, 25, 32, 15, 35, 24, 38, 33, 41, 16, 44, 19, 47, 40, 50, 34, 53, 21, 56, 48, 59, 22, 62, 27, 65, 55, 68, 28, 71, 43, 74, 63, 77, 30, 80, 54, 83, 70, 86, 31, 89, 36, 92, 78, 95, 64, 98, 37, 101, 85, 104, 39
(list; graph; listen)
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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.
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EXAMPLE
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The largest proper divisor of 8 is 4. So a(8) is the 4th integer from among those not occurring among the first 7 integers of the sequence (a(8) is the 4th integer from among 7,9,10,11,13,14,..). So a(8) = 11.
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MATHEMATICA
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f[l_List] := Block[{k = 0, c = Divisors[Length[l] + 1][[ -2]]}, While[c > 0, k++; While[MemberQ[l, k], k++ ]; c--; ]; Append[l, k]]; Nest[f, {1}, 71] (*Chandler*)
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CROSSREFS
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Cf. A126918, A032742.
Adjacent sequences: A126914 A126915 A126916 this_sequence A126918 A126919 A126920
Sequence in context: A089557 A083464 A065561 this_sequence A086496 A102398 A118317
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KEYWORD
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nonn
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AUTHOR
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Leroy Quet (qq-quet(AT)mindspring.com), Dec 31 2006
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EXTENSIONS
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Extended by Ray Chandler (rayjchandler(AT)sbcglobal.net), Jan 04 2007
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