Divisor Sum

You are given an integer $N$. Consider an array $A = [1,2, \ldots, N]$. An operation on array $A$ is defined as: - Erase all elements of the array $A$; - For each erased element $X$, insert all **positive** [divisors](https://en.wikipedia.org/wiki/Divisor) of $X$ into $A$. Find the sum of all elements of $A$ after $K$ operations. Since this sum can be huge, print it modulo $10^9 +7$. ### Inpu