If an=an−1+an−2a_n = a_{n-1} + a_{n-2}an=an−1+an−2, and we want ana_nan to grow as 3n3^n3n, what must be true about the coefficients?
3 must be a root of the characteristic equation
The coefficients must sum to 3
It is impossible for this specific recurrence
The first term must be 3