Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).
%I #19 Dec 10 2024 05:27:32
%S 0,1,2,3,8,9,27,29,50,60,252,651,1617,7374,8051,11391,17328,32382,
%T 35433
%N Numbers k such that 2^(2*k)-(2*k-1) is prime.
%C a(18) > 30000, if it exists. - _Amiram Eldar_, Dec 01 2021
%t Select[Range[0,2000],PrimeQ[2^(2#)-(2#-1)]&] (* _Harvey P. Dale_, May 20 2012 *)
%o (PARI) for(x=0,1000,if(isprime(2^(2*x)-(2*x-1)),print1(x,",")))
%Y Cf. A100102.
%K nonn,more
%O 1,3
%A _Jorge Coveiro_, Jul 25 2006
%E a(14)-a(17) from _Amiram Eldar_, Dec 01 2021
%E a(18)-a(19) from _Michael S. Branicky_, May 15 2023