Solve an=an−1+2na_n = a_{n-1} + 2nan=an−1+2n with a0=0a_0 = 0a0=0. What is ana_nan?
n(n+1)n(n+1)n(n+1)
n2n^2n2
2n22n^22n2
n(n−1)n(n-1)n(n−1)