A093174 Primes of the form 40*R_k + 1, where R_k is the repunit (A002275) of length k.

41, 4441, 44444444441, 4444444444444444444444444441, 4444444444444444444444444444444444444444444444444444441, 4444444444444444444444444444444444444444444444444444444444444444444444444444444444444444444441

Offset: 1

Author

Rick L. Shepherd, Mar 27 2004

Keywords

• nonn

Comments

Primes of the form (4*10^k - 31)/9. - Vincenzo Librandi, Nov 16 2010

Links

• Makoto Kamada, Prime numbers of the form 44...441.
• Index entries for primes involving repunits

Crossrefs

Cf. A056681 (corresponding k), A173768.

Extensions

Edited by N. J. A. Sloane, Feb 26 2010