Initially when you just buy your computer the price will be intact.
So for year 0, the price of your computer is 540.
For the next year, the price of the computer is 540÷3 = 180
So for year 1, the price of your computer is 180
and then for year 2, the price of your computer is 180÷3=60
So for year 2, the price of your computer is 60
Therefore the table would look like this
0 -----------> 540
1 ------------> 180
2 ------------> 60