%N Numbers n such that p=prime(n) is substring of 2^p-1.
%C p=prime such that p is substring of 2^p-1 in A086110.
%e a(2)=12 because prime(12)=37 is substring of 2^37-1=137438953471.
%Y Cf. A086110.
%A _Zak Seidov_, Jul 10 2003