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Search: id:A127011
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| A127011 |
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a(1)=1. a(n) = the numerator of the sum of the reciprocals of the earlier terms of the sequence which divide n. |
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+0
2
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| 1, 1, 2, 5, 11, 5, 2, 3, 7, 17, 23, 10, 2, 51, 41, 7, 35, 23, 2, 9, 55, 45, 48, 13, 12, 53, 22, 30, 2, 161, 2, 5, 80, 86, 102, 199, 2, 11, 94, 31, 83, 257, 2, 137, 46, 281, 2, 111, 16, 36, 41, 171, 107, 125, 14, 48, 7, 13, 2, 163, 2, 467, 181, 121, 179, 266, 2, 137, 167, 323, 2
(list; graph; listen)
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OFFSET
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1,3
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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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The sequence's terms, among terms a(1) through a(9), which divide 10 are a(1)=1, a(2)=1, a(3)=2, a(4)=5, a(6)=5 and a(7)=2. So a(10) is the numerator of 1 +1 +1/2 +1/5 +1/5 +1/2 = 17/5, which is 17.
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MATHEMATICA
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f[l_List] := Sum[1/l[[k]], {k, Length[l]}]; g[l_List] := Block[{n = Length[l] + 1}, Append[l, Numerator@f[Select[l, Mod[n, # ] == 0 &]]]]; Nest[g, {1}, 70] (*Chandler*)
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CROSSREFS
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Cf. A127012.
Sequence in context: A133516 A163784 A018862 this_sequence A069162 A079008 A144573
Adjacent sequences: A127008 A127009 A127010 this_sequence A127012 A127013 A127014
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KEYWORD
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nonn
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AUTHOR
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Leroy Quet Jan 02 2007
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EXTENSIONS
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Extended by Ray Chandler (rayjchandler(AT)sbcglobal.net), Jan 04 2007
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