A059528 Numbers k such that (7*3^k + 5)/2 is prime.

1, 3, 5, 15, 21, 27, 65, 191, 327, 371, 575, 1895, 2375, 2607, 9735, 48951

Offset

1,2

Comments

a(16) > 20055. - Jinyuan Wang, Jan 29 2020

Links

Table of n, a(n) for n=1..16.

Mathematica

Do[ If[ PrimeQ[ (7*3^n + 5)/2 ], Print[n] ], {n, 0, 5300} ]

Prog

(PARI) is(n)=ispseudoprime((7*3^n+5)/2) \\ Charles R Greathouse IV, Jun 13 2017

Crossrefs

Cf. A059569 ((7*3^k-5)/2 is prime).

Sequence in context: A208854 A165260 A201874 * A070079 A142717 A057742

Adjacent sequences: A059525 A059526 A059527 * A059529 A059530 A059531

Keyword

nonn,more

Author

Robert G. Wilson v, Feb 16 2001

Extensions

a(15) from Jinyuan Wang, Jan 29 2020

a(16) from Michael S. Branicky, Jul 08 2024

Status

approved