Write a function that takes a positive integer n, sums all the cubed values from 1 to n, and returns that sum.
Assume that the input n will always be a positive integer.
Examples: (Input --> output)
2 --> 9 (sum of the cubes of 1 and 2 is 1 + 8)
3 --> 36 (sum of the cubes of 1, 2, and 3 is 1 + 8 + 27)