I'm pretty sure this has been asked here before. But perhaps due to high flexibility in formulating this problem I couldn't find any useful resources.
Obviously a lower bound is $2$. And, numerically testing it in WolframAlpha, I'm quite convinced the limit should just be $2$.
My first thought was to see it as a Riemann partial sum but it failed, at least in the equi-partition case.
Could anybody help? Thanks.