A227046 - OEIS

%I #8 Feb 17 2017 15:40:30

%S 3,29,151,2153,5717,9133,9973,79537

%N Numbers n such that (17^n + 5^n)/22 is prime.

%C All terms are primes.

%C a(9) > 10^5.

%t k=17; Do[p=Prime[n]; f=(k^p+5^p)/(k+5); If[ PrimeQ[f], Print[p] ], {n, 1, 9592}]

%o (PARI) is(n)=ispseudoprime((17^n+5^n)/22) \\ _Charles R Greathouse IV_, Feb 17 2017

%Y Cf. A128340, A128341, A128342, A128343, A057183.

%K hard,more,nonn

%O 1,1

%A _Robert Price_, Jun 29 2013