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 A128350 Numbers k such that (14^k - 5^k)/9 is prime. 18
 2, 151, 673, 709, 2999, 17909, 77213 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS All terms are primes. a(8) > 10^5. - Robert Price, Apr 23 2013 LINKS Table of n, a(n) for n=1..7. MATHEMATICA k=14; Do[p=Prime[n]; f=(k^p-5^p)/(k-5); If[ PrimeQ[f], Print[p] ], {n, 1, 200}] PROG (PARI) is(n)=isprime((14^n-5^n)/9) \\ Charles R Greathouse IV, Feb 17 2017 CROSSREFS Cf. A062572, A128344, A128345, A128346, A128347, A128348, A128349, A128351, A128352, A128353, A128354. Cf. A004061, A082182, A121877, A059802. Cf. A057171, A082387, A122853, A128335, A128336, A128337, A128338, A128339, A128340, A128341, A128342. Sequence in context: A141130 A157074 A329712 * A046473 A261967 A024245 Adjacent sequences: A128347 A128348 A128349 * A128351 A128352 A128353 KEYWORD hard,more,nonn AUTHOR Alexander Adamchuk, Feb 27 2007 EXTENSIONS One more term from Herman Jamke (hermanjamke(AT)fastmail.fm), May 01 2008 a(6) and a(7) from Robert Price, Apr 23 2013 STATUS approved

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Last modified April 15 14:56 EDT 2024. Contains 371691 sequences. (Running on oeis4.)