A098863 Numbers k such that (6^k)*(2^k - 1) - 1 is prime.

1, 2, 3, 7, 8, 152, 206, 686, 1194, 1610, 10886, 20516

Offset

1,2

Comments

All terms under 5000 correspond to certified primes. (Primo 2.2.0 beta). - Ryan Propper, Apr 03 2006

a(11) > 9500. - Jinyuan Wang, Mar 19 2020

Links

Table of n, a(n) for n=1..12.

Prog

(PARI) is(n)=ispseudoprime((6^n)*(2^n-1)-1) \\ Charles R Greathouse IV, Jun 13 2017
(Magma) [k: k in [1..300] | IsPrime((6^k)*(2^k-1)-1)]; // Jinyuan Wang, Mar 19 2020

Crossrefs

Cf. A098864 ((6^k)*(2^k - 1) + 1 is prime).

Sequence in context: A038034 A103173 A378270 * A053960 A114056 A378827

Adjacent sequences: A098860 A098861 A098862 * A098864 A098865 A098866

Keyword

nonn,more

Author

Pierre CAMI, Oct 12 2004

Extensions

a(11)-a(12) from Michael S. Branicky, Mar 21 2023

Status

approved