I asked this list on Saturday about deletable primes. Thanks to everyone who replied. But no one answered my specific question about the largest known deletable prime, so I'm adding these two sequences to the OEIS. Maybe someone would like to extend them!
%S A125589 2,13,103,1013,10039 %N A125589 Smallest n-digit base-10 deletable prime.
100103, 1000193, 10000931
%S A125590 7,97,997,9973,99929 %N A125590 Largest n-digit base-10 deletable prime.
999907, 9999907, 99999307 I'm sure it's easy to go farther; this is what I have sitting around from our 2003 discussion, when we were busy counting them. I also think these ought to cross-reference to A096243, "Number of n-digit base-10 deletable primes", rather than to A096246, which has to do with base-2 deletables. --Michael Kleber -- It is very dark and after 2000. If you continue you are likely to be eaten by a bleen.