

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
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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
Bfile corrected by Ray Chandler, Oct 23 2011


STATUS

approved



