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Search: id:A127012
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| A127012 |
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a(0)=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, 2, 3, 2, 23, 2, 4, 7, 4, 2, 16, 2, 36, 7, 89, 2, 35, 2, 13, 55, 6, 47, 7, 2, 171, 7, 53, 2, 15, 2, 129, 7, 15, 96, 307, 2, 8, 94, 69, 2, 68, 2, 19, 37, 208, 95, 163, 19, 9, 7, 249, 107, 173, 111, 587, 139, 9, 2, 319, 2, 10, 215, 171, 27, 21, 2, 749, 55, 402, 2, 99, 2, 853, 37
(list; graph; listen)
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OFFSET
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0,3
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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(0) through a(8), which divide 9 are a(0)=1, a(1)=1 and a(4)=3. So a(9) is the numerator of 1 +1 +1/3 = 7/3, which is 7.
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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]}, Append[l, Numerator@f[Select[l, Mod[n, # ] == 0 &]]]]; Nest[g, {1}, 75] (*Chandler*)
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CROSSREFS
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Cf. A127011.
Sequence in context: A016009 A110088 A064998 this_sequence A125503 A127009 A164089
Adjacent sequences: A127009 A127010 A127011 this_sequence A127013 A127014 A127015
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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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