A216181 - OEIS

%I #14 Feb 20 2017 14:46:16

%S 3,5,11,17,71,89,827,22307,45893,63521

%N Numbers n such that (11^n - 4^n)/7 is prime.

%C All terms are prime.

%C Next term > 10^5.

%t Select[Prime[Range[1, 100000]], PrimeQ[(11^# - 4^#)/7]&]

%o (PARI) is(n)=ispseudoprime((11^n-4^n)/7) \\ _Charles R Greathouse IV_, Feb 20 2017

%Y Cf. A004063, A028491, A057468, A059801, A121877, A128024, A128025, A128026, A128027, A128028, A128029, A128030, A128031, A128032, A210506.

%K nonn,hard,more

%O 1,1

%A _Robert Price_, Mar 11 2013