A213216 - OEIS

%I #21 Feb 20 2017 14:46:19

%S 47,401,509,8609

%N Numbers n such that (12^n + 11^n)/23 is prime.

%C All terms are prime.

%C a(5) > 10^5.

%t Select[ Prime[ Range[1, 100000] ], PrimeQ[ (12^# + 11^#)/23 ]& ]

%o (PARI) is(n)=ispseudoprime((12^n+11^n)/23) \\ _Charles R Greathouse IV_, Feb 20 2017

%Y Cf. A057178, A128341, A181141, A187819, A217095.

%K hard,nonn,more

%O 1,1

%A _Robert Price_, Mar 02 2013

%E Removed incorrect first term of "2".