A108332 Integers k such that 10^k - 89 is prime.

2, 3, 637, 2349, 29455, 175093

Offset: 1

Author

Julien Peter Benney (jpbenney(AT)ftml.net), Jun 30 2005

Keywords

• nonn
• more

Comments

637 corresponds to a certified prime (Primo 2.2.0 beta). - Ryan Propper, Nov 06 2005

No additional terms < 40000.

See Kamada link - primecount.txt for terms, primesize.txt for discovery details including probable or proved primes - search on "9w11".

Examples

			k = 3 is a term because 10^3 - 89 = 1000 - 89 = 911, which is prime.
		

Links

• Makoto Kamada, List of near-repdigit-related prime numbers.
• Index entries for primes involving repunits.

Crossrefs

Cf. A089675, A095714, A092767.

Programs

Mathematica

Do[If[PrimeQ[10^n - 89], Print[n]], {n, 2, 10^4}] (* Ryan Propper, Nov 06 2005 *)

Extensions

a(5) from Robert Price, Dec 15 2010

Edited by Ray Chandler, Dec 23 2010

a(6) from Riley Fisher, Oct 09 2023