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 A128072 Numbers k such that (3^k + 14^k)/17 is prime. 10
 3, 7, 71, 251, 1429, 2131, 2689, 36683, 60763 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS All terms are primes. a(10) > 10^5. - Robert Price, Apr 20 2013 LINKS MATHEMATICA k=14; Do[ p=Prime[n]; f=(3^p+k^p)/(k+3); If[ PrimeQ[f], Print[p]], {n, 1, 100} ] PROG (PARI) is(n)=isprime((3^n+14^n)/17) \\ Charles R Greathouse IV, Feb 17 2017 CROSSREFS Cf. A007658 = numbers n such that (3^n + 1)/4 is prime. Cf. A057469 = numbers n such that (3^n + 2^n)/5 is prime. Cf. A122853 = numbers n such that (3^n + 5^n)/8 is prime. Cf. A128066, A128067, A128068, A128069, A128070, A128071, A128073, A128074, A128075. 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, A128031, A128032. Sequence in context: A261136 A127179 A113841 * A094008 A209477 A209336 Adjacent sequences:  A128069 A128070 A128071 * A128073 A128074 A128075 KEYWORD hard,more,nonn AUTHOR Alexander Adamchuk, Feb 14 2007 EXTENSIONS 3 more terms from Ryan Propper, Jan 28 2008 a(8)-a(9) from Robert Price, Apr 20 2013 STATUS approved

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Last modified July 2 02:41 EDT 2020. Contains 335389 sequences. (Running on oeis4.)