Calculate all possible permutations of dataset - 60 numbers on 3 positions

I use a scale of $0-$15000, divided by brackets of $250. Hence, in total there are 15000/250=60 values possible (250, 500, 750, ..., 15000).

There are three possible positions x1, x2 and x3.

I need an excel sheet with all possible combinations/permutations, with (if possible) the following exception:
x3>x2>x1

So I need an Excel sheet that will look as follows:

x1	250	250	250	250		250	500	500		14500
x2	500	500	500	500	....	500	750	750	....	14750
x3	750	1000	1250	1500		15000	1000	1250		15000

Is there an efficient way to get all combinations/permutations?