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Search: id:A127009
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| A127009 |
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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 are coprime to n. |
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+0
2
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| 1, 1, 2, 2, 3, 2, 23, 164, 13389, 243985, 15948790008791, 182889846746034804193, 46520575190667784168670190084854378399767989073, 33107435283268333623593822288321538682200992783751408959931533910313916858227252\ 552270
(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(7), which are coprime to 8 are a(1)=1, a(2)=1, a(5)=3 and a(7) = 23. So a(8) is the numerator of 1 +1 +1/3 +1/23 = 164/69, which is 164.
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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, GCD[ #, n] == 1 &]]]]; Nest[g, {1}, 13] (*Chandler*)
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CROSSREFS
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Cf. A127010.
Sequence in context: A064998 A127012 A125503 this_sequence A164089 A068460 A143797
Adjacent sequences: A127006 A127007 A127008 this_sequence A127010 A127011 A127012
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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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