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A058025
Numbers k such that 3*13^k - 2 is prime.
1
1, 5, 11, 16, 59, 239, 299, 2524, 2695, 7657, 14028, 24104, 28068
OFFSET
1,2
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 A376332 A123082
KEYWORD
nonn,more
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