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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. 1
1, 1, 2, 5, 11, 57, 126, 17609, 127439468, 344473534513077, 891027683693605833852, 156052046552117500148945259643265853536683707838813 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

LINKS

Table of n, a(n) for n=0..11.

EXAMPLE

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.

MATHEMATICA

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*)

CROSSREFS

Cf. A127009.

Sequence in context: A089609 A277041 A087185 * A140547 A131480 A262228

Adjacent sequences:  A127007 A127008 A127009 * A127011 A127012 A127013

KEYWORD

nonn

AUTHOR

Leroy Quet, Jan 02 2007

EXTENSIONS

Extended by Ray Chandler, Jan 04 2007

STATUS

approved

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Last modified February 24 22:41 EST 2018. Contains 299627 sequences. (Running on oeis4.)