OEIS says a Brazilian number is...
> numbers n such that there is a natural number b with 1 < b < n-1 such that the representation of n in base b has all equal digits.
I don't know what my problem is, erou had used almost the same wording, but I found myself incapable to get it.
For even more fun, try this search instead:
Nice find, @erou, thanks!
A Mastodon instance for maths people. The kind of people who make \(\pi z^2 \times a\) jokes.
\) for inline LaTeX, and
\] for display mode.