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 A128336 Numbers n such that (6^n + 5^n)/11 is prime. 26
 3, 5, 17, 397, 409, 643, 1783, 2617, 4583, 8783 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS All terms are primes. No other terms less than 100000. - Robert Price, May 11 2012. LINKS MATHEMATICA k=6; Do[p=Prime[n]; f=(k^p+5^p)/(k+5); If[ PrimeQ[f], Print[p] ], {n, 1, 100}] PROG (PARI) forprime(p=3, 1e4, if(ispseudoprime((6^p+5^p)/11), print1(p", "))) \\ Charles R Greathouse IV, Jul 16 2011 CROSSREFS 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. Sequence in context: A123599 A100270 A016045 * A278735 A094487 A007516 Adjacent sequences:  A128333 A128334 A128335 * A128337 A128338 A128339 KEYWORD hard,more,nonn AUTHOR Alexander Adamchuk, Feb 27 2007 EXTENSIONS a(7)-a(9) from Alexander Adamchuk, May 04 2010 One more term (8783) added (unknown discoverer) corresponding to a probable prime with 6834 digits by Jean-Louis Charton, Oct 06 2010 STATUS approved

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Last modified October 23 09:45 EDT 2019. Contains 328345 sequences. (Running on oeis4.)