A366323 Numbers k such that (k*3^k - 1)/2 is a prime.

5, 25, 125, 389, 549, 1125, 12889, 26925

Offset

1,1

Comments

Odd terms of A242274.

Links

Table of n, a(n) for n=1..8.

Example

k = 5 is a term: (5*3^5 - 1)/2 = 607 is a prime.

Crossrefs

Cf. A242274.

Sequence in context: A061974 A015950 A337950 * A267780 A228736 A126642

Adjacent sequences: A366320 A366321 A366322 * A366324 A366325 A366326

Keyword

nonn,hard,more

Author

Jon E. Schoenfield, Oct 06 2023

Extensions

a(8) from Michael S. Branicky, Oct 08 2024

Status

approved