A217134 - OEIS

%I #9 Feb 04 2014 00:53:08

%S 2,4,10,14,88,112,140,764,3040,11096,24934,25616,54584,93400

%N Numbers n such that 5^n - 8 is prime.

%C a(15) > 10^5. - _Robert Price_, Feb 03 2014

%t Select[Range[2, 5000], PrimeQ[5^# - 8] &]

%o (PARI) for(n=2, 5*10^3, if(isprime(5^n-8), print1(n", ")))

%Y Cf. A059613, A087885, A089142, A109080, A124621, A165701.

%K nonn

%O 1,1

%A _Vincenzo Librandi_, Oct 01 2012

%E a(10)-a(14) from _Robert Price_, Feb 03 2014