A093171 Primes of the form 80*R_k + 7, where R_k is the repunit (A002275) of length k.

7, 887, 8887, 888887, 888888887, 888888888887, 888888888888888888888888888888888888888888888888888888888888888888888887

Offset: 1

Author

Rick L. Shepherd, Mar 26 2004

Keywords

• nonn

Comments

Primes of the form (8*10^k - 17)/9. - Vincenzo Librandi, Nov 16 2010

Links

• Makoto Kamada, Prime numbers of the form 88...887.
• Index entries for primes involving repunits

Crossrefs

Cf. A056695 (corresponding k), A096846.