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A056214
Primes p whose period of reciprocal equals (p-1)/9.
12
73, 1423, 1459, 2377, 2503, 3457, 7741, 9433, 10891, 10909, 16057, 17299, 17623, 20269, 21313, 22699, 24103, 26263, 28621, 28927, 29629, 30817, 32257, 34273, 34327, 35461, 35731, 36343, 36793, 37549, 37567, 37657, 38737, 39367, 39979
OFFSET
1,1
COMMENTS
Cyclic numbers of the ninth degree (or ninth order): the reciprocals of these numbers belong to one of nine different cycles. Each cycle has the (number minus 1)/9 digits.
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, 5000]], f[ # ] == 9 &]
KEYWORD
nonn,base
AUTHOR
Robert G. Wilson v, Aug 02 2000
EXTENSIONS
Edited by N. J. A. Sloane, Apr 30 2007
STATUS
approved