In a number theory course around 1990, I remember reading papers from the 60s which would explicitly note whether the counts of primes that they were using were starting from 1 or 2. You can define them as not notable mathematicians, but working mathematicians in number theory still had not completely standardized 50 years ago.

Now for more fun, sit down with a group of mathematicians and ask whether they consider 0 to be a natural number. :-)

(The answer you get will vary by field. But none will consider it a particularly important question.)