An Algorithm for Ennola's Second Theorem and Counting Smooth Numbers in Practice

Chloe Makdad, Jonathan P. Sorenson

Let $\Psi (x,y)$ count the number of positive integers $n\le x$ such that every prime divisor of $n$ is at most $y$. Given inputs $x$ and $y$, what is the best way to estimate $\Psi (x,y)$…