Find the smallest prime containing
every nonprime digit.
(In reply to
re(2): solution via computer my remarks by Charlie)
In the first 100 numbers having all of the nonprime digits, the interloping primes can occur only in the 7digit numbers as we haven't arrived at 8digit numbers yet. The interloping prime can only be 3 or 7 and not 5, as the nonprimes, 0, 1, 4, 6, 8 and 9, add up to 28 and the addition of 5 would make 33, so all such numbers would be a multiple of 3 and therefore not prime. You'd have to get into the 8digit numbers, with either a repetition of a nonprime, or another prime (or a second 5) to get a case with all the primes and also at least one 5.

Posted by Charlie
on 20170428 15:38:57 