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A171058
Numbers k such that 3^k + 3*k + 1 is prime.
4
0, 1, 3, 41, 45, 83, 95, 181, 193, 195, 311, 325, 901, 1825, 3649, 7709, 16335, 45547
OFFSET
1,3
COMMENTS
a(19) > 10^5. - Michael S. Branicky, Jul 25 2024
PROG
(PARI) is(n)=ispseudoprime(3^n+3*n+1) \\ Charles R Greathouse IV, Jun 13 2017
CROSSREFS
Numbers k such that b^k + b*k + 1 is prime: A301634 (b=2), this sequence (b=3), A301635 (b=5).
Sequence in context: A295612 A350545 A286661 * A105906 A157009 A100765
KEYWORD
nonn,more
AUTHOR
N. J. A. Sloane, Sep 04 2010, based on a posting to the Sequence Fans Mailing List by Charles R Greathouse IV, Aug 23 2010
EXTENSIONS
More terms from Charles R Greathouse IV, Sep 07 2010
STATUS
approved