A247959 Numbers n such that 39^n + 2 is prime.

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

Links

Table of n, a(n) for n=1..17.

Henri & Renaud Lifchitz, PRP Top Records, Search for 39^n + 2.

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

Adjacent sequences: A247956 A247957 A247958 * A247960 A247961 A247962

Keyword

nonn,more

Author

Vincenzo Librandi, Sep 28 2014

Extensions

a(14)-a(17) from Robert Price, Apr 14 2015

Status

approved