Apattern is made by toothpick squares. select the series that represents the number of toothpicks added to a picture to get the next picture to the right. pretend the first picture has no toothpicks.
4 + 12 + 24 + 40 + ; rule is an = 2(n2 + n)
1 + 2 + 3 + 4 + ; rule is an = n
1 + 4 + 9 + 16 + ; rule is an = n2
4 + 8 + 12 + 16 + ; rule is an = 4n

the first one has one square the next one has 4 the next one has 9 and the last one has 16