Search: id:A127010
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%I A127010
%S A127010 1,1,2,5,11,57,126,17609,127439468,344473534513077,
%T A127010 891027683693605833852,
%U A127010 156052046552117500148945259643265853536683707838813
%N A127010 a(0)=1. a(n) = the numerator of the sum of the reciprocals of the earlier 
               terms of the sequence which are coprime to n.
%H A127010 Leroy Quet, <a href="http://www.prism-of-spirals.net/">Home Page</a> 
               (listed in lieu of email address)
%e A127010 The sequence's terms, among terms a(0) through a(5), which are coprime 
               to 6 are a(0)=1,a(1)=1,a(3)=5 and a(4)=11. So a(6) is the numerator 
               of 1 +1 +1/5 +1/11 = 126/55, which is 126.
%t A127010 f[l_List] := Sum[1/l[[k]], {k, Length[l]}];g[l_List] := Block[{n = Length[l]},
               Append[l, Numerator@f[Select[l, GCD[ #, n] == 1 &]]]];Nest[g, {1}, 
               12] (*Chandler*)
%Y A127010 Cf. A127009.
%Y A127010 Sequence in context: A106887 A089609 A087185 this_sequence A131480 A018847 
               A134996
%Y A127010 Adjacent sequences: A127007 A127008 A127009 this_sequence A127011 A127012 
               A127013
%K A127010 nonn
%O A127010 0,3
%A A127010 Leroy Quet Jan 02 2007
%E A127010 Extended by Ray Chandler (rayjchandler(AT)sbcglobal.net), Jan 04 2007

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