A171514 Numbers k such that 1 + 8*10^k + 100^k is prime.

1, 3, 6, 9, 13, 17, 29, 63, 90, 531, 14286, 30617, 37815

Offset: 1

Author

Jason Earls, Dec 10 2009

Keywords

• more
• hard
• nonn

Comments

No more terms up to k = 7500.

14286, 30617, and 37815, found by Daniel Heuer in 2001-2002, are also terms; see Caldwell link. - Jeppe Stig Nielsen, Jan 30 2022

Links

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

Crossrefs

Cf. A171376, A171411, A171459, A171554.

Programs

Mathematica

Select[Range[1000], PrimeQ[1 + 8 10^# + 100^# ] &] (* Vincenzo Librandi, Apr 26 2014 *)

PARI

is(n)=ispseudoprime(1+8*10^n+100^n) \\ Charles R Greathouse IV, Jun 13 2017

Extensions

a(11)-a(13) from Lucas A. Brown, Mar 04 2024