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A357612
Numbers k such that 1 + 2^k*k^3 is prime.
4
1, 5, 41, 202, 281, 394, 1157, 1211, 1816, 9845, 19780, 50800, 98621, 101945
OFFSET
1,2
EXAMPLE
1 is in this sequence because 1 + 2^1*1^3 = 5 is prime;
5 is in this sequence because 1 + 2^5*5^3 = 4001 is prime.
MATHEMATICA
Select[Range[2000], PrimeQ[1 + 2^# * #^3] &] (* Amiram Eldar, Nov 17 2022 *)
PROG
(Magma) [n: n in [1..2000] | IsPrime(1+2^n*n^3)];
CROSSREFS
KEYWORD
nonn,more,hard
AUTHOR
EXTENSIONS
a(11)-a(12) from Amiram Eldar, Nov 17 2022
a(13)-a(14) from Michael S. Branicky, May 16 2023
STATUS
approved