A093402 Primes of the form 40*R_k + 9, where R_k is the repunit (A002275) of length k.

449, 44449, 444449, 444444444444444444444444444444444444444444444449, 444444444444444444444444444444444444444444444444444444444444444444444444444444444444444444444444444444444449

Offset: 1

Author

Rick L. Shepherd, Mar 28 2004

Keywords

• nonn

Comments

Primes of the form (4*10^k + 41)/9. - Vincenzo Librandi, Nov 16 2010

Links

• Makoto Kamada, Prime numbers of the form 44...449.
• Index entries for primes involving repunits

Crossrefs

Cf. A056683 (corresponding k).

Programs

Mathematica

Select[Table[FromDigits[PadLeft[{9},n,4]],{n,120}],PrimeQ] (* Harvey P. Dale, May 21 2011 *)