|
Search: id:A127077
|
|
|
| A127077 |
|
a(1)=1. a(n) = a(n-1) + (product of the earlier terms {among terms a(1) through a(n-1)} which are coprime to n). |
|
+0
2
|
|
| 1, 2, 4, 5, 13, 78, 40638, 40703, 21206263, 11221082003820, 15964509207021745126354079410538220, 15964509207021745126410184714526005
(list; graph; listen)
|
|
|
OFFSET
|
1,2
|
|
|
LINKS
|
Leroy Quet, Home Page (listed in lieu of email address)
|
|
EXAMPLE
|
The terms of the sequence, among terms a(1) through a(5), which are coprime to 6 are a(1)=1, a(4)=5 and a(5) = 13. So a(6) = a(5) + 1*5*13 = 78.
|
|
MATHEMATICA
|
f[l_List] := Append[l, l[[ -1]] + Times @@ Select[l, GCD[ #, Length[l] + 1] == 1 &]]; Nest[f, {1}, 15] (*Chandler*)
|
|
CROSSREFS
|
Cf. A127078.
Sequence in context: A078652 A102992 A136563 this_sequence A104549 A000063 A039574
Adjacent sequences: A127074 A127075 A127076 this_sequence A127078 A127079 A127080
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
Leroy Quet Jan 04 2007
|
|
EXTENSIONS
|
Extended by Ray Chandler (rayjchandler(AT)sbcglobal.net), Jan 06 2007
|
|
|
Search completed in 0.002 seconds
|
