%I #2 Mar 30 2012 17:26:27
%S 3,13,23,3,43,53,3,73,83,3,103,113,23,13,43,53,163,173,83,193,3,13,
%T 223,233,43,53,263,73,283,293,3,313,23,3,43,353,3,373,383,3,3,41,23,
%U 433,443,53,463,73,83,3,503,13,523,53,43,53,563,73,83,593,3,613,23,3,643,653,3
%N Largest prime visible as a substring of 10n+3.
%e a(0)=3 because 10*0+3=3 (prime),
%e a(1)=13 because 10*1+3=13 (prime),
%e a(3)=3 because 10*3+3=33 (composite)=>3 (prime),
%e a(78)=83 because 10*78+3=783 (composite) =>83 (prime).
%K nonn,base
%O 0,1
%A _Zak Seidov_, Feb 24 2008