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, 2, 5, 11, 57, 126, 17609, 127439468, 344473534513077, 891027683693605833852, 156052046552117500148945259643265853536683707838813

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] (* Ray Chandler, Jan 04 2007 *)

Crossrefs

Cf. A127009.

Sequence in context: A362525 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