%I #28 Sep 08 2022 08:46:10
%S 0,1,9,23,681,2487
%N Numbers n such that 41^n + 2 is prime.
%C All terms > 0 are odd. - _Robert Israel_, Sep 29 2014
%C a(7) > 2*10^5. - _Robert Price_, May 08 2015
%t Select[Range[0, 2000], PrimeQ[41^# + 2] &]
%o (Magma) [n: n in [0..600]| IsPrime( 41^n + 2 )];
%o (PARI) is(n)=ispseudoprime(41^n+2) \\ _Charles R Greathouse IV_, Jun 13 2017
%Y Cf. similar sequences listed in A247957.
%K nonn,more
%O 1,3
%A _Vincenzo Librandi_, Sep 29 2014