A058025 Numbers k such that 3*13^k - 2 is prime.

1, 5, 11, 16, 59, 239, 299, 2524, 2695, 7657, 14028, 24104, 28068

Offset

1,2

Links

Table of n, a(n) for n=1..13.

Example

3(13^5) - 2 = 1113877, which is a prime number, hence 5 is in the sequence.
3(13^7) - 2 = 188245549, but that is divisible by 211, hence 7 is NOT a term.

Mathematica

Do[ If[ PrimeQ[ 3*13^n - 2 ], Print[ n ] ], {n, 0, 1500} ] (* RGWv *)
Select[Range[0, 4000], PrimeQ[(3*13^# - 2)] &] (* Vincenzo Librandi, Sep 28 2012 *)

Prog

(PARI) is(n)=ispseudoprime(3*13^n-2) \\ Charles R Greathouse IV, Jun 13 2017

Crossrefs

Cf. A057871 (3*13^k + 2 is prime).

Sequence in context: A041046 A041117 A041491 * A042121 A123082 A084037

Adjacent sequences: A058022 A058023 A058024 * A058026 A058027 A058028

Keyword

nonn,more,changed

Author

Robert G. Wilson v, Nov 15 2000

Extensions

a(8)-a(9) from Vincenzo Librandi, Sep 28 2012

a(10) from Bruno Berselli, Sep 28 2012

a(11) from Jinyuan Wang, Feb 02 2020

a(12) from Michael S. Branicky, Jun 29 2023

a(13) from Michael S. Branicky, Jul 28 2024

Status

approved