This table shows the average price per pound for peanut butter in the United States from 2011 to 2014. What type of relationship do the data show?

Use mathematical induction to prove the statement is true for all positive integers n, or show why it is false. 1^2 + 4^2 + 7^2 + + (3n - 2)^2 = [n(6n^2-3n-1)/2]