It is an open problem whether the number $\pi$ is disjunctive in base $10$, i.e., whether every finite sequence appears (at least once) in the base $10$ expansion of $\pi$. Of course, every sequence of length $1$ appears, and it is readily checked that so does every sequence of length $2$. I guess the same can be easily checked for other small lengths, and has surely been done before. So, my question is the following:

For which natural numbers $n$ is it known that every sequence of length $n$ appears in the base $10$ expansion of $\pi$?

Searching the internet somewhat longer I found that this is known to be true for $n$ at most $7$. Surely there must be much better bounds...