A171411 Numbers k such that 1 + 5*10^k + 100^k is prime.

0, 1, 2, 4, 5, 8, 27, 165, 230, 237, 369, 485, 628, 875, 964, 1419, 4083

Offset: 1

Author

Jason Earls, Dec 08 2009

Keywords

• nonn
• more

Comments

No more terms up to k=7600. The value corresponding to 4083 was certified prime with WinPFGW.

a(18) > 30000. - Michael S. Branicky, May 15 2025

Links

• Chris K. Caldwell, Prime Pages, Database Search Output

Crossrefs

Cf. A171376, A171459, A171514, A171554.

Programs

PARI

is(n)=ispseudoprime(1+5*10^n+100^n) \\ Charles R Greathouse IV, Jun 13 2017