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

Offset

1,2

Comments

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

Links

Table of n, a(n) for n=1..15.

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

Status

approved