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.
LINKS
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 &]
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Robert G. Wilson v, Aug 02 2000
EXTENSIONS
Edited by N. J. A. Sloane, Apr 30 2007
STATUS
approved