login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A128948 Primes p for which the period length of 1/p is a perfect power, A001597. 4
3, 17, 73, 101, 137, 163, 257, 353, 449, 577, 641, 751, 757, 883, 1297, 1409, 1801, 3137, 3529, 5477, 7057, 7351, 8929, 9397, 10753, 11831, 12101, 13457, 13553, 14401, 15361, 15377, 15973, 18523, 19841, 20809, 21401, 21601, 23549, 24001, 24337 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Number of primes p < 10^n whose period length of 1/p is a perfect power: 1,3,14,24,78,173,461,1190,3235,8933,....

The primes modulo any integer do not seem to be equally distributed.

LINKS

Ray Chandler & Robert G. Wilson v, Table of n, a(n) for n = 1..30000

Index entries for sequences related to decimal expansion of 1/n

EXAMPLE

The prime 73 has a period of 8 = 2^3 which is a member of A001597, hence is a member of this sequence.

MATHEMATICA

lst = {3}; p = 1; While[p < 10^8, p = NextPrime@p; If[GCD @@ Last /@ FactorInteger@ MultiplicativeOrder[10, p] > 1, AppendTo[lst, p]; Print@p]]; lst (* Chandler *)

CROSSREFS

Cf. A001597, A072859, A072982.

Sequence in context: A270231 A265919 A317452 * A049181 A248917 A282400

Adjacent sequences:  A128945 A128946 A128947 * A128949 A128950 A128951

KEYWORD

base,nonn

AUTHOR

Robert G. Wilson v, May 05 2007

EXTENSIONS

Correction (3 is a member of the sequence) from Ray Chandler, May 11 2007

B-file corrected by Ray Chandler, Oct 23 2011

STATUS

approved

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

License Agreements, Terms of Use, Privacy Policy. .

Last modified June 18 18:52 EDT 2019. Contains 324215 sequences. (Running on oeis4.)