Solve an=4an−1−4an−2a_n = 4a_{n-1} - 4a_{n-2}an=4an−1−4an−2 with a0=1,a1=4a_0=1, a_1=4a0=1,a1=4.
an=(n+1)2na_n = (n+1) 2^nan=(n+1)2n
an=2na_n = 2^nan=2n
an=4na_n = 4^nan=4n
an=2n+1a_n = 2n + 1an=2n+1