This triangle shape full of numbers is the reference I have to use for the first part of a homework problem, but I haven't the slightest clue as to why the rows and columns are indexed starting at zero and what that means in terms of all the other rows.
That being said:
How does P(4,2)=6?
It doesn't make any sense to me.
Note: I used parentheses to make up for the fact that I couldn't type in a small '4' and a small '2'.