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Numbers k such that k^8*2^k - 1 is a prime.
0

%I #19 Aug 29 2024 12:14:29

%S 5,7,49,165,251,345,385,945,949,1001,1963,2113,2249,3751,4381,4911,

%T 5133,10039,29693,34901,73885,99319,104883,113613

%N Numbers k such that k^8*2^k - 1 is a prime.

%t Select[Range[5000], PrimeQ[#^8*2^# - 1] &] (* _Amiram Eldar_, Nov 23 2023 *)

%o (Magma) [k: k in [1..4000] | IsPrime(k^8*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), A367478 (m = 6), A367561 (m = 7), this sequence (m = 8).

%K nonn,more

%O 1,1

%A _Juri-Stepan Gerasimov_, Nov 23 2023

%E a(19)-a(20) from _Michael S. Branicky_, Nov 23 2023

%E a(21) from _Michael S. Branicky_, Nov 25 2023

%E a(22)-a(24) from _Michael S. Branicky_, Aug 29 2024