OFFSET
1,2
COMMENTS
The even members of A005538, halved. - Jeppe Stig Nielsen, Oct 13 2019
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 *)
PROG
(PARI) is(n)=ispseudoprime(8*9^n+1) \\ Charles R Greathouse IV, Mar 01 2017
CROSSREFS
KEYWORD
nonn,more
AUTHOR
Robert G. Wilson v, Aug 22 2000
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
STATUS
approved