Given an=an−1+2n−1a_n = a_{n-1} + 2n - 1an=an−1+2n−1, find the closed form for ana_nan with a0=0a_0 = 0a0=0.
an=n2a_n = n^2an=n2
an=2na_n = 2nan=2n
an=n2−1a_n = n^2 - 1an=n2−1
an=n(n+1)a_n = n(n+1)an=n(n+1)