|
%I #7 Jun 13 2017 10:30:45
%S 2,5,19,109,157,8521,26017,26177
%N Numbers n such that (13^n - 4^n)/9 is prime.
%C All terms are prime.
%C a(9) > 10^5.
%t Select[Prime[Range[1, 100000]], PrimeQ[(13^# - 4^#)/9]&]
%o (PARI) is(n)=ispseudoprime((13^n-4^n)/9) \\ _Charles R Greathouse IV_, Jun 13 2017
%Y Cf. A004063, A028491, A057468, A059801, A121877, A128024, A128025, A128026, A128027, A128028, A128029, A128030, A128031, A128032, A210506, A128347.
%K nonn,hard,more
%O 1,1
%A _Robert Price_, Apr 15 2013
|
