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A197225
Primes p with the period of the decimal fraction 1/p a prime power, A000961.
2
3, 11, 17, 37, 41, 53, 73, 79, 83, 101, 107, 137, 163, 173, 227, 239, 257, 271, 317, 347, 353, 359, 449, 467, 479, 563, 587, 641, 643, 719, 733, 751, 757, 773, 797, 839, 907, 1031, 1187, 1231, 1283, 1307, 1319, 1409, 1439, 1493, 1523, 1627, 1637, 1879, 1907
OFFSET
1,1
MATHEMATICA
myPerfectPowerQ[n_] := Length[FactorInteger[n]] == 1; Select[Prime[Range[500]], Mod[10, #] > 0 && myPerfectPowerQ[Length[RealDigits[1/#, 10][[1, 1]]]] &]
CROSSREFS
Cf. A072859 (period is prime).
Cf. A072982 (period is a power of 2).
Cf. A128948 (period is perfect power).
Cf. A197226 (the periods of this sequence).
Cf. A129727 (period is a semiprime).
Sequence in context: A186424 A018520 A154933 * A181507 A154934 A302872
KEYWORD
nonn,base
AUTHOR
T. D. Noe, Oct 22 2011
STATUS
approved