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Numbers k such that k^6*2^k - 1 is a prime.
3

%I #19 Nov 21 2023 17:16:36

%S 37,43,167,217,239,349,581,1297,5183,9119,10589,15205,18745,25687,

%T 26609,33667,35663,73603,82501,89269

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

%t Select[Range[6000], PrimeQ[#^6*2^# - 1] &] (* _Amiram Eldar_, Nov 19 2023 *)

%o (Magma) [k: k in [1..1000] | IsPrime(k^6*2^k-1)];

%Y Numbers k such that k^m*2^k - 1 is a prime: A000043 (m = 0), A002234 (m = 1), A058781 (m = 2), A367037 (m = 3), A367102 (m = 4), A367464 (m = 5), this sequence (m = 6).

%K nonn,more

%O 1,1

%A _Juri-Stepan Gerasimov_, Nov 19 2023

%E a(12) inserted by and a(14)-a(17) from _Michael S. Branicky_, Nov 19 2023

%E a(18)-a(20) from _Michael S. Branicky_, Nov 21 2023