Which of these is a non-homogeneous linear recurrence relation?
an=3an−1+2an−2a_n = 3a_{n-1} + 2a_{n-2}an=3an−1+2an−2
an=2an−1+na_n = 2a_{n-1} + nan=2an−1+n
an=an−1⋅an−2a_n = a_{n-1} \cdot a_{n-2}an=an−1⋅an−2
an=an−1+an−3a_n = a_{n-1} + a_{n-3}an=an−1+an−3