A230139 - OEIS

%I #6 Jun 13 2017 14:28:44

%S 3,5,7,11,31,101,887,4861

%N Numbers n such that (17^n - 4^n)/13 is prime.

%C All terms are prime.

%C a(9) > 10^5.

%t Select[Prime[Range[1, 100000]], PrimeQ[(17^# - 4^#)/13]&]

%o (PARI) is(n)=ispseudoprime((17^n-4^n)/13) \\ _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, A128352, A225807.

%K nonn,hard,more

%O 1,1

%A _Robert Price_, Oct 10 2013