Characteristic eq for an=61an−1+an−2a_n = 61a_{n-1} + a_{n-2}an=61an−1+an−2.
r2+61r−1=0r^2 + 61r - 1 = 0r2+61r−1=0
r2−61r+1=0r^2 - 61r + 1 = 0r2−61r+1=0
r2−61r−1=0r^2 - 61r - 1 = 0r2−61r−1=0
r2+61r+1=0r^2 + 61r + 1 = 0r2+61r+1=0