%I A138602
%S A138602 20,21,22,23,32,33,83,140,1122
%N A138602 Numbers n such that 2^(2*n-39)-39 is prime.
%e A138602 2^(2*23-39)-39=89, 2^(2*32-39)-39=33554393, 2^(2*33-39)-39=134217689, 
               2^(2*83-39)-39=170141183460469231731687303715884105689,
%t A138602 q=39;For[i=q,i<=q,a={};Do[x=2^(2*n-i)-i;If[PrimeQ[x],AppendTo[a,n]],{n,
               12^3}];Print["2^(2*n-",i,")-",i," ",a];i=i+2]
%Y A138602 Sequence in context: A008553 A007930 A133895 this_sequence A030605 A063780 
               A125663
%Y A138602 Adjacent sequences: A138599 A138600 A138601 this_sequence A138603 A138604 
               A138605
%K A138602 nonn
%O A138602 1,1
%A A138602 Vladimir Orlovsky (4vladimir(AT)gmail.com), May 13 2008