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Search: id:A127417
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| A127417 |
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a(1)=1; for n > 1, a(n) = number of earlier terms a(k), 1<k<=n-1, such that (a(k)+n) is divisible by k. |
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+0
2
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| 1, 1, 2, 2, 2, 2, 3, 2, 2, 4, 3, 1, 4, 3, 2, 5, 2, 4, 4, 1, 2, 6, 4, 1, 6, 3, 3, 5, 2, 4, 3, 4, 3, 6, 4, 2, 3, 5, 5, 4, 3, 3, 7, 2, 2, 7, 4, 3, 5, 3, 4, 5, 6, 3, 3, 4, 2, 6, 6, 4, 6, 4, 5, 3, 3, 5, 5, 3, 3, 7, 6, 2, 6, 5, 4, 5, 2, 5, 8, 1, 5, 6, 5, 1, 6, 7, 3, 9, 2, 4, 5, 2, 5, 6, 6, 5, 5, 4, 4, 6, 4, 4, 6, 3, 4
(list; graph; listen)
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OFFSET
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1,3
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COMMENT
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The value of a(1) = 1 is arbitrary. a(1) can be any integer and the rest of the sequence would remain unchanged.
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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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a(1)+11 = 12 is a multiple of 1; a(2)+11 = 12 is a multiple of 2; and a(7)+11 = 14 is a multiple of 7. These 3 are the only cases where (a(k)+11) is a multiple of k, for 1 <=k <=10. So a(11) = 3.
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MATHEMATICA
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f[l_List] := Block[{n = Length[l] + 1}, Append[l, Count[Table[Mod[l[[k]] + n, k], {k, n - 1}], 0]]]; Nest[f, {1}, 105] (*Chandler*)
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CROSSREFS
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Cf. A127418.
Sequence in context: A127992 A067595 A134868 this_sequence A128764 A074589 A165035
Adjacent sequences: A127414 A127415 A127416 this_sequence A127418 A127419 A127420
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KEYWORD
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nonn
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AUTHOR
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Leroy Quet Jan 13 2007
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EXTENSIONS
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Extended by Ray Chandler (rayjchandler(AT)sbcglobal.net), Jan 22 2007
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