A127463 a(0)=1. a(n) = number of earlier terms a(k), 0<=k<=n-1, such that (k+a(k)) is coprime to n.

1, 1, 1, 2, 3, 4, 3, 6, 7, 5, 6, 11, 4, 12, 8, 9, 9, 17, 6, 19, 6, 13, 10, 23, 6, 20, 10, 18, 11, 29, 3, 31, 14, 19, 14, 26, 7, 37, 16, 22, 11, 41, 8, 42, 18, 25, 19, 47, 11, 46, 13, 32, 21, 53, 15, 40, 25, 36, 29, 58, 9, 59, 31, 36, 34, 46, 16, 67, 33, 41, 24, 71, 17, 72, 37, 37, 37

Offset

0,4

Links

Table of n, a(n) for n=0..76.

Example

(a(0)+0) is coprime to 12; (a(3)+3) is coprime to 12; (a(4)+4) is coprime to 12; and (a(7)+7) is coprime to 12. These 4 cases are the only cases where (a(k)+k) is coprime to 12, for 0<=k<=11. So a(12)=4.

Mathematica

f[l_List] := Block[{n = Length[l]}, Append[l, Count[Table[GCD[n, k - 1 + l[[k]]], {k, n}], 1]]]; Nest[f, {1}, 78] (* Ray Chandler, Jan 22 2007 *)

Crossrefs

Cf. A127461, A127462.

Sequence in context: A347123 A318510 A048276 * A076618 A116550 A283165

Adjacent sequences: A127460 A127461 A127462 * A127464 A127465 A127466

Keyword

nonn

Author

Leroy Quet, Jan 15 2007

Extensions

Extended by Ray Chandler, Jan 22 2007

Status

approved