A217382 Numbers k such that 8^k + 9 is prime.

1, 2, 3, 6, 10, 19, 22, 109, 798, 1498, 1519, 3109, 5491, 13351, 26983, 48799, 57909, 98109

Offset: 1

Author

Vincenzo Librandi, Oct 03 2012

Keywords

• nonn
• more

Comments

All terms are equal to 1/3 of the multiples of 3 in A057196.

Crossrefs

Cf. A057196, A217354, A217355.

Cf. A145440 (associated primes).

Programs

Mathematica

Select[Range[10000], PrimeQ[8^# + 9] &]

PARI

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

Extensions

a(16)-a(18) from Michael S. Branicky, May 17 2025 using b-file at A057196