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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. 1
1, 1, 2, 2, 3, 2, 23, 164, 13389, 243985, 15948790008791, 182889846746034804193, 46520575190667784168670190084854378399767989073, 33107435283268333623593822288321538682200992783751408959931533910313916858227252552270 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

LINKS

Table of n, a(n) for n=1..14.

EXAMPLE

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.

MATHEMATICA

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] (* Ray Chandler, Jan 04 2007 *)

CROSSREFS

Cf. A127010.

Sequence in context: A297935 A127012 A125503 * A181313 A334515 A164089

Adjacent sequences:  A127006 A127007 A127008 * A127010 A127011 A127012

KEYWORD

nonn

AUTHOR

Leroy Quet, Jan 02 2007

EXTENSIONS

Extended by Ray Chandler, Jan 04 2007

STATUS

approved

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Last modified July 2 12:39 EDT 2022. Contains 355004 sequences. (Running on oeis4.)