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 A216889 Numbers n such that 12*3^n + 1 is prime. 1
 0, 1, 2, 5, 13, 14, 38, 200, 248, 884, 1004, 1253, 1634, 3305, 3521, 9601, 19784, 72697 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 COMMENTS a(19) > 2*10^5. - Robert Price, Mar 16 2014 All terms are verified primes (ie, not probable primes). - Robert Price, Mar 16 2014 LINKS FORMULA a(n) = A005537(n+1)-1. - Bruno Berselli, Sep 27 2012 MATHEMATICA Select[Range[4000], PrimeQ[12 * 3^# + 1] &] PROG (MAGMA) [n: n in [0..4000] | IsPrime(12*3^n + 1)]; (PARI) is(n)=ispseudoprime(12*3^n+1) \\ Charles R Greathouse IV, Jun 13 2017 CROSSREFS Cf. A003306, A005537-A005539, A056805. Sequence in context: A247543 A220268 A049476 * A168486 A038914 A019419 Adjacent sequences:  A216886 A216887 A216888 * A216890 A216891 A216892 KEYWORD nonn AUTHOR Vincenzo Librandi, Sep 26 2012 EXTENSIONS a(16)-a(17) from Vincenzo Librandi, Sep 30 2012 a(18) from Robert Price, Mar 16 2014 STATUS approved

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Last modified January 19 18:13 EST 2020. Contains 331051 sequences. (Running on oeis4.)