%I #21 Aug 12 2023 17:15:34
%S 2,3,4,7,40,59,140
%N Numbers k such that cyclotomic(k, 2^k) is a prime number.
%C No other terms below 300. - _Max Alekseyev_, May 29 2009
%C No other terms below 760. - _Lucas A. Brown_, Dec 16 2020
%e 4 is a term because cyclotomic(4,16) = 1 + 16^2 = 257 is prime.
%t Do[s=Cyclotomic[n, 2^n]; If[PrimeQ[s], Print[n]], {n, 1, 1000}]
%t Select[Range[150],PrimeQ[Cyclotomic[#,2^#]]&] (* _Harvey P. Dale_, Aug 12 2023 *)
%o (PARI) isok(k) = isprime(polcyclo(k, 2^k)); \\ _Michel Marcus_, Dec 17 2020
%Y Cf. A070518-A070526.
%K more,nonn
%O 1,1
%A _Labos Elemer_, May 02 2002
%E One more term from _Max Alekseyev_, May 29 2009