A155905 - OEIS

%I #4 Mar 30 2012 17:28:50

%S 0,1,2,3,4,6,7,10,11,12,13,14,15,17,18,19,20,21,22,24,25,27,30,31,33,

%T 36,38,42,43,46,49,50,51,54,55,57,58,60,64,65,73,74,84,93,106,108,123,

%U 126,129,139,150,162,183,187,196,198,220,271,273,279,301,312,379,392

%N Numbers n such that it is possible to append a single digit to the end of 2^n to make it prime.

%C Expected to be infinite because the harmonic series diverges.

%e For example 641 and 1283 are prime so 6 and 7 are in the sequence respectively.

%K nonn,base

%O 1,3

%A _Dmitry Kamenetsky_, Jan 30 2009