Question 567156
Let S_n be the sum of the first n odd (positive) integers (e.g. S_n = 1+3+...+(2n-1))


n---S_n
1   1
2   4
3   9
4   16
k   k^2
80  80^2 = 6400


It can be proved using induction that the sum of the first k odd integers is k^2.