%I #11 Jul 14 2023 09:02:15
%S 1,2,6,14,66,86,230,2006,3876,3920,5418,8820,11900,16669,19446,28243,
%T 33408,37919,40595
%N Numbers k such that 2^(k-1)+2*k-1 is a prime number.
%t Select[Range[4000], PrimeQ[2^(# - 1) + 2# - 1] &] (* _Alonso del Arte_, Jul 09 2011 *)
%o (PARI) for(n=1,10^6,if(ispseudoprime(2^(n-1)+2*n-1),print1(n,", ")));
%Y Cf. A004051, A163115, A176691, A192436.
%K nonn,more
%O 1,2
%A _Juri-Stepan Gerasimov_, Jul 09 2011
%E a(13)-a(19) from _Michael S. Branicky_, Jul 14 2023
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