# Greetings from The On-Line Encyclopedia of Integer Sequences! http://oeis.org/ Search: id:a128336 Showing 1-1 of 1 %I A128336 #19 Jun 11 2021 00:10:16 %S A128336 3,5,17,397,409,643,1783,2617,4583,8783 %N A128336 Numbers k such that (6^k + 5^k)/11 is prime. %C A128336 All terms are primes. %C A128336 No other terms less than 100000. - _Robert Price_, May 11 2012 %t A128336 k=6; Do[p=Prime[n]; f=(k^p+5^p)/(k+5); If[ PrimeQ[f], Print[p] ], {n,1,100}] %o A128336 (PARI) forprime(p=3,1e4,if(ispseudoprime((6^p+5^p)/11),print1(p", "))) \\ _Charles R Greathouse IV_, Jul 16 2011 %Y A128336 Cf. A057171, A082387, A122853, A128335, A128337, A128338, A128339, A128340, A128341, A128342, A128343, A004061, A082182, A121877, A059802, A062572, A128344, A128345, A128346, A128347, A128348, A128349, A128350, A128351, A128352, A128353, A128354. %K A128336 hard,more,nonn %O A128336 1,1 %A A128336 _Alexander Adamchuk_, Feb 27 2007 %E A128336 a(7)-a(9) from _Alexander Adamchuk_, May 04 2010 %E A128336 One more term (8783) added (unknown discoverer) corresponding to a probable prime with 6834 digits by _Jean-Louis Charton_, Oct 06 2010 # Content is available under The OEIS End-User License Agreement: http://oeis.org/LICENSE