login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 59th year, we have over 358,000 sequences, and we’ve crossed 10,300 citations (which often say “discovered thanks to the OEIS”).

Other ways to Give
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A054717 Number of powers of 9 modulo n. 4
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 (list; graph; refs; listen; history; text; internal format)
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

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified November 27 19:48 EST 2022. Contains 358406 sequences. (Running on oeis4.)