VOOZH about

URL: https://oeis.org/A217383

⇱ A217383 - OEIS

login
A217383
Numbers k such that 8^k - 9 is prime.
1
3, 7, 11, 47, 81, 95, 107, 179, 233, 243, 947, 2817, 2859, 3233, 7563, 11307, 218615, 225587, 1160027
OFFSET
1,1
COMMENTS
All terms are equal to 1/3 of the multiples of 3 in A059610.
Naturally these numbers are odd since 8^(2n)-9 = (8^n-3)(8^n+3) is composite. - Bruno Berselli, Oct 04 2012
MATHEMATICA
Select[Range[10000], PrimeQ[8^# - 9] &]
PROG
(PARI) is(n)=ispseudoprime(8^n-9) \\ Charles R Greathouse IV, Jun 13 2017
CROSSREFS
KEYWORD
nonn,more
AUTHOR
Vincenzo Librandi, Oct 03 2012
EXTENSIONS
a(17)-a(18) using A059610 from Michael S. Branicky, Jul 14 2023
a(19) using A059610 from Michael S. Branicky, Apr 23 2025
STATUS
approved