If the sequence ana_nan satisfies an=c12n+c2(−2)na_n = c_1 2^n + c_2 (-2)^nan=c12n+c2(−2)n, what is the recurrence?
an=4an−2a_n = 4a_{n-2}an=4an−2
an=2an−1a_n = 2a_{n-1}an=2an−1
an=an−1+4an−2a_n = a_{n-1} + 4a_{n-2}an=an−1+4an−2
an=2an−2a_n = 2a_{n-2}an=2an−2