negative memory usage

[Gribouillis]

the usage of memory is shown as a negative number! why?

I think it is negative because the code deletes the previously calculated list cubes. You could correct this by running

del cubes
m3 = ...

Another major problem with your code is that the call to check_even_gene() creates a generator but it does not actually calculate the data num * num, so it basically does nothing.

Also note that num * num is not the cube of the number num.