A006559 - OEIS

A006559

Short period primes: the decimal expansion of 1/p has period less than p-1, but greater than zero.
(Formerly M2881)

3, 11, 13, 31, 37, 41, 43, 53, 67, 71, 73, 79, 83, 89, 101, 103, 107, 127, 137, 139, 151, 157, 163, 173, 191, 197, 199, 211, 227, 239, 241, 251, 271, 277, 281, 283, 293, 307, 311, 317, 331, 347, 349, 353, 359, 373, 397, 401, 409, 421, 431, 439, 443, 449, 457

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

COMMENTS

Primes 2 and 5 are excluded because 1/2 and 1/5 have no period. Also primes p whose multiplicative order mod p is less than p-1.

REFERENCES

N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

LINKS

T. D. Noe, Table of n, a(n) for n = 1..1000

Victor Meally, Letter to N. J. A. Sloane, no date.

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

MATHEMATICA