Erdős Problem 969

### What is the conjecture

https://www.erdosproblems.com/969

Let $Q(x)$ count the number of squarefree integers in $[1,x]$. Determine the order of magnitude in the error term in the asymptotic
$$Q(x)=\frac{6}{\pi^2}x+E(x).$$

Status: open

### Choose either option
- [ ] I plan on working on this conjecture
- [x] This issue is up for grabs: I would like to see this conjecture added by somebody else

Start by reading the linked Erdős Problems page for Problem 969 and the conjecture stated in this issue. The task is complete when the squarefree-counting asymptotic and its error-term question have been formally added to the Lean collection; this issue does not name an existing file, entry point, or test to run.

Written by the indexing model from the issue text.