A056799 Numbers n such that 8*9^n +1 is prime.

1, 4, 5, 11, 26, 29, 38, 65, 166, 490, 641, 2300, 9440, 44741, 65296, 161930, 586240

Offset: 1

Author

Robert G. Wilson v, Aug 22 2000

Keywords

• nonn
• more

Comments

The even members of A005538, halved. - Jeppe Stig Nielsen, Oct 13 2019

Crossrefs

Cf. A005538.

Programs

Mathematica

Do[If[PrimeQ[8*9^n + 1], Print[n]], {n, 0, 1000}]
Select[Range[3000], PrimeQ[8 9^# + 1] &] (* Vincenzo Librandi, Sep 28 2012 *)

PARI

is(n)=ispseudoprime(8*9^n+1) \\ Charles R Greathouse IV, Mar 01 2017

Extensions

a(12) from Vincenzo Librandi, Sep 28 2012

a(13)-a(16) from Robert Price, Feb 22 2016

a(17) from Paul S. Vanderveen, Jul 04 2020