What is the recursive formula for the sequence? 2, 20, 300, 6000, 150000, ... Oa1 = 2, an = nan-1 Oal = 2, an = 5an-1 - n Oa1 = 2, an = 5 + nan-1 Oa1 = 2, an = n+ 5an-1 Oal = 2, an = 5nan-1 X