Consider the recurrence an=n⋅an−1a_n = n \cdot a_{n-1}an=n⋅an−1 with a0=1a_0 = 1a0=1. What is the closed form for ana_nan?
an=n2a_n = n^2an=n2
an=n!a_n = n!an=n!
an=2na_n = 2^nan=2n
an=n2na_n = n^{2n}an=n2n