Search: id:A127009
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%I A127009
%S A127009 1,1,2,2,3,2,23,164,13389,243985,15948790008791,182889846746034804193,
%T A127009 46520575190667784168670190084854378399767989073,
%U A127009 33107435283268333623593822288321538682200992783751408959931533910313916858227252552270
%N A127009 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.
%H A127009 Leroy Quet, <a href="http://www.prism-of-spirals.net/">Home Page</a> 
               (listed in lieu of email address)
%e A127009 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.
%t A127009 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*)
%Y A127009 Cf. A127010.
%Y A127009 Sequence in context: A064998 A127012 A125503 this_sequence A164089 A068460 
               A143797
%Y A127009 Adjacent sequences: A127006 A127007 A127008 this_sequence A127010 A127011 
               A127012
%K A127009 nonn
%O A127009 1,3
%A A127009 Leroy Quet Jan 02 2007
%E A127009 Extended by Ray Chandler (rayjchandler(AT)sbcglobal.net), Jan 04 2007

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