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A247959
Numbers n such that 39^n + 2 is prime.
1
0, 1, 2, 5, 6, 13, 22, 93, 99, 132, 217, 539, 1185, 28840, 70666, 105456, 116749
OFFSET
1,3
COMMENTS
Numbers ending with 4 are not in the sequence, since 39^n+2 is divisible by 11 for such numbers. - Bruno Berselli and M. F. Hasler, Oct 02 2014
a(18) > 2*10^5. - Robert Price, Apr 14 2015
MATHEMATICA
Select[Range[0, 2000], PrimeQ[39^# + 2] &]
PROG
(Magma) [n: n in [0..500]| IsPrime(39^n+2)];
(PARI) for(n=0, 9e9, ispseudoprime(39^n+2)&&print1(n", ")) \\ M. F. Hasler, Oct 02 2014
CROSSREFS
Cf. similar sequences listed in A247957.
Sequence in context: A321472 A087128 A154365 * A243799 A029544 A058668
KEYWORD
nonn,more
AUTHOR
Vincenzo Librandi, Sep 28 2014
EXTENSIONS
a(14)-a(17) from Robert Price, Apr 14 2015
STATUS
approved