|
| |
|
|
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; internal format)
|
|
|
|
OFFSET
| 1,3
|
|
|
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] (*Chandler*)
|
|
|
CROSSREFS
| Cf. A127010.
Sequence in context: A064998 A127012 A125503 * A181313 A164089 A068460
Adjacent sequences: A127006 A127007 A127008 * A127010 A127011 A127012
|
|
|
KEYWORD
| nonn
|
|
|
AUTHOR
| Leroy Quet Jan 02 2007
|
|
|
EXTENSIONS
| Extended by Ray Chandler (rayjchandler(AT)sbcglobal.net), Jan 04 2007
|
| |
|
|
