A054717 Number of powers of 9 modulo n.

1, 1, 2, 1, 2, 2, 3, 1, 2, 2, 5, 2, 3, 3, 3, 2, 8, 2, 9, 2, 4, 5, 11, 2, 10, 3, 3, 3, 14, 3, 15, 4, 6, 8, 6, 2, 9, 9, 4, 2, 4, 4, 21, 5, 3, 11, 23, 3, 21, 10, 9, 3, 26, 3, 10, 3, 10, 14, 29, 3, 5, 15, 4, 8, 6, 6, 11, 8, 12, 6, 35, 2, 6, 9, 11, 9, 15, 4, 39, 2, 3, 4, 41, 4, 8, 21, 15, 5, 44, 3, 3

Offset

1,3

Links

David W. Wilson, Table of n, a(n) for n = 1..1000

Example

Take the sequence 1, 9, 81, 729, ... and reduce mod n; count distinct terms. For n = 5 we get 1, 4, 1, 4, ... so a(5) = 2.

Mathematica

With[{p9=9^Range[0, 50]}, Table[Length[Union[Mod[#, n]&/@p9]], {n, 100}]] (* Harvey P. Dale, Apr 22 2012 *)

Crossrefs

Sequence in context: A333939 A272759 A272760 * A086421 A290399 A109400

Adjacent sequences: A054714 A054715 A054716 * A054718 A054719 A054720

Keyword

easy,nonn

Author

Henry Bottomley, Apr 20 2000

Status

approved