For an integer , we define the lower prime square root of , denoted by , as the largest prime and the upper prime square root of , , as the smallest prime .
So, for example, , , .
Let us call an integer semidivisible, if one of and divides , but not both.
The sum of the semidivisible numbers not exceeding is , the numbers are , and . is not semidivisible because it is a multiple of both and .
As a further example, the sum of the semidivisible numbers up to is .
What is the sum of all semidivisible numbers not exceeding ?
Write-up coming later
The complete problem is available here. An approach, code, and answer will be added later.