A268356 Numbers n such that 8*9^n - 1 is prime.

0, 1, 2, 5, 25, 85, 92, 97, 649, 2017, 2978, 3577, 4985, 17978, 21365, 66002, 95305, 142199

Offset: 1

Author

Robert Price, Feb 02 2016

Keywords

• nonn
• more

Comments

a(19) > 2*10^5.

Crossrefs

Cf. A056799, A198966.

Programs

Mathematica

Select[Range[0, 200000], PrimeQ[8*9^# - 1] &] (* Robert Price, Feb 02 2016 *)

PARI

is(n)=ispseudoprime(8*9^n-1) \\ Charles R Greathouse IV, Jun 13 2017