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A093171
Primes of the form 80*R_k + 7, where R_k is the repunit (A002275) of length k.
4
7, 887, 8887, 888887, 888888887, 888888888887, 888888888888888888888888888888888888888888888888888888888888888888888887
OFFSET
1,1
COMMENTS
Primes of the form (8*10^k - 17)/9. - Vincenzo Librandi, Nov 16 2010
CROSSREFS
Cf. A056695 (corresponding k), A096846.
Sequence in context: A193342 A298301 A332187 * A330295 A177908 A127102
KEYWORD
nonn
AUTHOR
Rick L. Shepherd, Mar 26 2004
STATUS
approved