Proving the Nth digit of pi exists is not (necessarily) constructive. Though to make it an actual proof and not a truism you might say "when writing pi in the

Proving the Nth digit of pi exists is not (necessarily) constructive. Though to make it an actual proof and not a truism you might say "when writing pi in the shortest decimal representation, there is a millionth digit". Proving pi is irrational would suffice, without actually calculating the first million digits.