> Here, his sweatshirt lists the first 20 digitally delicate primes. Isn't the first digitally delicate prime simply 2? Or are single-digit primes excluded? Or

> Here, his sweatshirt lists the first 20 digitally delicate primes. Isn't the first digitally delicate prime simply 2? Or are single-digit primes excluded? Or am I missing something terribly fundamental? edit Or is it that, because we can replace 2 by 3 and still get a prime, it doesn't count? Which is to say, replacing any digit in the number by any other digit, must always result in a non-prime?