A111023 Integers n such that 9*10^n + 11 is a prime number.

1, 2, 3, 4, 6, 8, 16, 20, 27, 115, 180, 274, 576, 1111, 2404, 5127, 8082, 9514, 12808, 14752, 15926, 22670, 37432, 41988, 53707, 72595, 92742

Offset: 1

Author

Julien Peter Benney (jpbenney(AT)ftml.net), Oct 04 2005

Keywords

• more
• nonn

Comments

See Kamada link - primecount.txt for terms, primesize.txt for discovery details including probable or proved primes - search on "90w11".

a(28) > 10^5. - Robert Price, Jan 28 2017

Examples

			n = 6 is a member because 9*10^6 + 11 = 9*1000000 + 11 = 9000011, which is prime.
		

Links

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

Crossrefs

Cf. A100275 = numbers n such that 9*10^n-11 is prime.

Cf. A049054, A088274, A088275, A095688, A107083, A108049, A108050, A108052, A108054, A110980.

Programs

Mathematica

Do[If[PrimeQ[9*10^n+11],Print[n]],{n,1,1300}] (* Zak Seidov, Sep 14 2006 *)

Extensions

Edited by N. J. A. Sloane, Apr 11 2008

a(16)-a(22) from Ray Chandler, Dec 23 2010

a(23)-a(27) from Robert Price, Jan 28 2017