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 A219039 Numbers n such that 3^n - 16 is prime. 16
 3, 5, 11, 15, 51, 69, 99, 227, 381, 537, 9135, 9737, 58437, 105567, 121779, 123645 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS a(17) > 2*10^5. - Robert Price, Sep 29 2013 LINKS EXAMPLE For n=3, a(3)=3^3-16=11 and 11 is prime. Hence n=3 is included in the sequence. MATHEMATICA Do[If[PrimeQ[3^n - 16], Print[n]], {n, 1, 10000}] PROG (PARI) is(n)=isprime(3^n-16) \\ Charles R Greathouse IV, Feb 17 2017 CROSSREFS Cf. Sequences of numbers n such that 3^n + m is prime:   (m = 2) A051783, (m = -2) A014224, (m = 4) A058958, (m = -4) A058959,   (m = 8) A217136, (m = -8) A217135, (m = 10) A217137, (m = -10) A217347,   (m = 14) A219035, (m = -14) A219038, (m = 16) A205647, (m = -16) this sequence, (m = 20) A219040, (m = -20) A219041.   Note that if m is a multiple of 3, 3^n + m is also a multiple of 3 (for n greater than 0), and as such isn't prime. Sequence in context: A318915 A322439 A018313 * A074820 A327043 A006169 Adjacent sequences:  A219036 A219037 A219038 * A219040 A219041 A219042 KEYWORD nonn AUTHOR Nicolas M. Perrault, Nov 10 2012 EXTENSIONS a(13)-a(16) from Robert Price, Sep 29 2013 STATUS approved

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Last modified July 6 08:51 EDT 2020. Contains 335476 sequences. (Running on oeis4.)