|
Search: id:A127462
|
|
|
| A127462 |
|
a(1)=1; for n>1, a(n) = number of earlier terms a(k), 1<=k<=n-1, such that (k+a(k)) is coprime to n. |
|
+0
3
|
|
| 1, 0, 2, 1, 2, 3, 5, 4, 5, 2, 10, 3, 12, 5, 5, 8, 16, 5, 17, 6, 9, 9, 21, 7, 18, 13, 15, 12, 28, 6, 28, 16, 16, 17, 22, 11, 36, 18, 20, 18, 40, 12, 41, 22, 18, 23, 45, 14, 40, 22, 26, 26, 52, 16, 41, 22, 27, 28, 56, 13, 60, 29, 26, 33, 49, 20, 66, 34, 34, 23, 70, 24, 70, 39, 33, 36, 56
(list; graph; listen)
|
|
|
OFFSET
|
1,3
|
|
|
LINKS
|
Leroy Quet, Home Page (listed in lieu of email address)
|
|
EXAMPLE
|
(a(3)+3) is coprime to 6; (a(4)+4) is coprime to 6; and (a(5)+5) is coprime to 6. These 3 cases are the only cases where (a(k)+k) is coprime to 6, for 1<=k<=5. So a(6)=3.
|
|
MATHEMATICA
|
f[l_List] := Block[{n = Length[l] + 1}, Append[l, Count[Table[GCD[n, k + l[[k]]], {k, n - 1}], 1]]]; Nest[f, {1}, 76] (*Chandler*)
|
|
CROSSREFS
|
Cf. A127460, A127463.
Sequence in context: A054502 A059346 A076492 this_sequence A106436 A075758 A125596
Adjacent sequences: A127459 A127460 A127461 this_sequence A127463 A127464 A127465
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
Leroy Quet Jan 15 2007
|
|
EXTENSIONS
|
Extended by Ray Chandler (rayjchandler(AT)sbcglobal.net), Jan 22 2007
|
|
|
Search completed in 0.002 seconds
|
