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 A128031 Numbers n such that (17^n - 3^n)/14 is prime. 28
 3, 11, 17, 491, 23029 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS All terms are primes. No other terms <100,000. LINKS MATHEMATICA k=14; Select[ Prime[ Range[1, 200] ], PrimeQ[ ((k+3)^# - 3^#)/k ]& ] PROG (PARI) is(n)=isprime((17^n-3^n)/14) \\ Charles R Greathouse IV, Feb 17 2017 CROSSREFS Cf. A028491 = numbers n such that (3^n - 1)/2 is prime. Cf. A057468 = numbers n such that 3^n - 2^n is prime. Cf. A059801 = numbers n such that 4^n - 3^n is prime. Cf. A121877 = numbers n such that (5^n - 3^n)/2 is a prime. Cf. A128024, A128025, A128026, A128027, A128028, A128029, A128030, A128032. Sequence in context: A080306 A036448 A128346 * A194128 A127995 A316839 Adjacent sequences:  A128028 A128029 A128030 * A128032 A128033 A128034 KEYWORD hard,more,nonn AUTHOR Alexander Adamchuk, Feb 11 2007 EXTENSIONS a(5)=23029 from Robert Price, Nov 03 2011 STATUS approved

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Last modified September 25 22:33 EDT 2020. Contains 337346 sequences. (Running on oeis4.)