A309854 - OEIS

%I #20 Oct 29 2023 22:00:47

%S 6,7,10,12,15,22,34,46,57,60,64,75,81,82,84,94,112,117,129,132,151,

%T 160,169,171,175,186,196,210,214,222,225,255,264,292,301,309,315,330,

%U 357,364,369,370,379,381,384,400,412,417,426,430,454,474,516,547,549,582,610,631,636,655

%N Numbers k such that 2*k^5 - 1 is prime.

%H Robert Israel, <a href="/A309854/b309854.txt">Table of n, a(n) for n = 1..10000</a>

%p filter:= k -> isprime(2*k^5-1):

%p select(filter, [$1..1000]); # _Robert Israel_, Oct 29 2023

%o (PARI) isok(k) = isprime(2*k^5 - 1); \\ _Michel Marcus_, Jul 22 2021

%Y Cf. A214289 (2*k^3 - 1 prime), A182783 (2*k^4 - 1 prime), A309855 (subset of primes).

%K nonn

%O 1,1

%A _R. J. Mathar_, Aug 20 2019