A057917 Numbers k such that 3*5^k - 2 is prime.

1, 2, 3, 4, 31, 34, 82, 116, 120, 398, 450, 566, 1216, 1478, 1776, 2379, 2816, 3492, 3644, 7348, 8374, 8406, 9931, 13311, 15358, 16120

Offset

1,2

Comments

a(27) > 21628. - Jinyuan Wang, Dec 14 2019

Links

Table of n, a(n) for n=1..26.

Mathematica

Do[ If[ PrimeQ[ 3*5^n - 2 ], Print[ n ] ], {n, 1, 1500} ]

Prog

(PARI) is(n)=ispseudoprime(3*5^n-2) \\ Charles R Greathouse IV, Jun 12 2017

Crossrefs

Cf. A057916 (3*5^k + 2 is prime).

Sequence in context: A064889 A351999 A356885 * A250189 A255253 A076592

Adjacent sequences: A057914 A057915 A057916 * A057918 A057919 A057920

Keyword

nonn,more

Author

Robert G. Wilson v, Nov 17 2000

Extensions

a(20)-a(26) from Jinyuan Wang, Dec 14 2019

Status

approved