A187872 - OEIS

%I #10 Nov 05 2020 05:36:37

%S 3,5,7,13,19,41,71,137,263,523,1033,2063,4111,8219,16417,32779,65539,

%T 131111,262151,524341,1048589,2097211,4194329,8388619,16777289,

%U 33554473,67108913,134217773,268435463,536870951,1073741831,2147483693

%N Second smallest prime after 2^n.

%H Robert Israel, <a href="/A187872/b187872.txt">Table of n, a(n) for n = 0..3318</a>

%e 2^2=4, second smallest prime=7;

%e 2^3=8, second smallest prime=13; ..

%p seq(nextprime(nextprime(2^n)),n=0..100); # _Robert Israel_, Nov 04 2020

%t NextPrime[2^Range[0,100], 2]

%o (PARI) a(n) = nextprime(nextprime(2^n+1)+1); \\ _Michel Marcus_, Nov 05 2020

%Y Cf. A007491, A014210.

%K nonn

%O 0,1

%A _Vladimir Joseph Stephan Orlovsky_, Mar 14 2011