How to find prime numbers where $\frac{1}{p}$ has decimal period of $p-1$? Is there any formula? please help. Example: $\frac{1}{7}=0.142857142857...$ with decimal period of $7-1=6$ also $17$ satisfies this condition, but $13$ does not.
Asked
Active
Viewed 1,101 times
4
-
3You need to check that $10$ is a generator $\pmod p$, see this article. there is no known method to efficiently list these. – lulu Nov 25 '16 at 12:44
-
wow did you cook up this problem? – User Not Found Nov 25 '16 at 12:49
-
I guess there should be a formula like the formula of "full reptend primes" – iman12 Nov 25 '16 at 13:03
-
See this answer. – Bill Dubuque Nov 25 '16 at 14:17