A171227 Numbers k such that 9 + 10^k + 9*100^k is prime.

0, 1, 4, 17, 26, 28, 47, 70, 91, 1129, 4334, 12347, 20212

Offset: 1

Author

Jason Earls, Dec 05 2009

Keywords

• more
• nonn

Comments

No more terms up to k = 4100.

Examples

			19, 919, 900010009 are prime so that 0, 1 and 4 are terms.
		

Crossrefs

Cf. A083816.

Programs

PARI

is(n)=ispseudoprime(9+10^n+9*100^n) \\ Charles R Greathouse IV, Jun 13 2017

Extensions

a(11)-a(12) from Michael S. Branicky, Jun 22 2023

a(13) from Michael S. Branicky, Nov 01 2024