If an=an−1+3a_n = a_{n-1} + 3an=an−1+3 and a0=1a_0 = 1a0=1, what is the closed-form for ana_nan?
an=3n+1a_n = 3n + 1an=3n+1
an=n+3a_n = n + 3an=n+3
an=3na_n = 3nan=3n
an=n3+1a_n = n^3 + 1an=n3+1