How to simply increase list size with code?

Basically I am wondering how to increase the size of a list to be a certain amount.

like if a number of 256 was the case then the list would match the number without increasing the size in
the inspector.

you could run a for and add 0’s to the number of wanted size I guess?

int size = 256;
List<int> list = new List<int>;
for(int i = 0; i < size; i++)
    {
        list.Add(0);
    }

this will increase the size in the inspector though. Maybe a custom inspector can do that? Not sure on that