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A056211 Primes p for which the period of reciprocal = (p-1)/6. 5
79, 547, 643, 751, 907, 997, 1201, 1213, 1237, 1249, 1483, 1489, 1627, 1723, 1747, 1831, 1879, 1987, 2053, 2551, 2683, 3049, 3253, 3319, 3613, 3919, 4159, 4507, 4519, 4801, 4813, 4831, 4969, 5119, 5443, 5557, 5791, 6079, 6151, 6271, 6373, 6427, 6529 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Cyclic numbers of the sixth degree (or sixth order): the reciprocals of these numbers belong to one of six different cycles. Each cycle has the (number minus 1)/6 digits.

LINKS

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

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

MATHEMATICA

f[n_Integer] := Block[{ds = Divisors[n - 1]}, (n - 1)/Take[ ds, Position[ PowerMod[ 10, ds, n], 1] [[1, 1]]] [[ -1]]]; Select[ Prime[ Range[4, 850]], f[ # ] == 6 &]

CROSSREFS

Cf. A001913, A097443, A055628, A056157, A056210-A056217, A098680

Sequence in context: A141563 A107954 A098673 * A139184 A142235 A251373

Adjacent sequences:  A056208 A056209 A056210 * A056212 A056213 A056214

KEYWORD

nonn,base

AUTHOR

Robert G. Wilson v, Aug 02 2000

EXTENSIONS

Edited by N. J. A. Sloane, Apr 30 2007

STATUS

approved

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Last modified January 22 23:00 EST 2019. Contains 319365 sequences. (Running on oeis4.)