This follows a pattern. If he makes 1 pot the first week and wants to make triple the following week he will make 3 pots the second week because 1x3=3.
The third week he would make triple the amount from the second week 3x3=9
This can also be simplified with exponents. in week 1 your equation would be
x = 1³ (answer is 3)
week 2 would be x = 2³ (answer is 9)
This pattern continues and you can find the amount of pots made in the 5th week by using the same equation (x = 5³)
x being the number of pots made