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

%I #19 Mar 22 2023 08:34:10

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

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

%C All terms under 5000 correspond to certified primes. (Primo 2.2.0 beta). - _Ryan Propper_, Apr 03 2006

%C a(11) > 9500. - _Jinyuan Wang_, Mar 19 2020

%o (PARI) is(n)=ispseudoprime((6^n)*(2^n-1)-1) \\ _Charles R Greathouse IV_, Jun 13 2017

%o (Magma) [k: k in [1..300] | IsPrime((6^k)*(2^k-1)-1)]; // _Jinyuan Wang_, Mar 19 2020

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

%K nonn,more

%O 1,2

%A _Pierre CAMI_, Oct 12 2004

%E a(11)-a(12) from _Michael S. Branicky_, Mar 21 2023