Done!

Ok, maybe you could add tag Optimization to this kata ? That could be the lead for people to have a clue what is happening or what is wrong.

You could look at : https://bkaestner.github.io/codewars-rules/#errors

I should not have infinite loops there, problem is it timeouts before anything could be printed out.
P.S. With tests I am able to do list_squared(1, 13000)

maybe your not excepting an edgecase which causes an infinite loop inside your method, you can log your inputs to debug your code. :)

Test cases are done in 27 ms but Submit timeouts with 6s

Are you timing out? The number are not that big.

(Python)As I read comments here, its not as much as broken as I had no clue why it was not passing, tests passed easily. I guess problem is optimization. Probably add some crazy big number so people will know what is the problem.

Which language please? Why broken?

Still 'broken'...

I know I could do it like this. You even can see it that I used it this way for is_set and I commented there that it can be done with cycle.

In the beginning I used this for more transparency and better understanding.