%I #5 May 27 2016 07:28:05

%S 2,3,11,163,191,269,1381,1493

%N Numbers n such that (11^n - 6^n)/5 is prime.

%C All terms are prime.

%C The corresponding primes: 17, 223, 56989774711, ...

%t Select[Range[1, 10000], PrimeQ[(11^# - 6^#)/5] &]

%o (PARI) for(n=1, 10000, if(isprime((11^n - 6^n)/5), print1(n, ", ")))

%Y Cf. A005808, A210506, A128027, A216181, A128347, A273599, A273600, A273601, A062577.

%K nonn,more,hard

%O 1,1

%A _Tim Johannes Ohrtmann_, May 26 2016