Characteristic eq for an=129an−1+an−2a_n = 129a_{n-1} + a_{n-2}an=129an−1+an−2.
r2+129r−1=0r^2 + 129r - 1 = 0r2+129r−1=0
r2+129r+1=0r^2 + 129r + 1 = 0r2+129r+1=0
r2−129r−1=0r^2 - 129r - 1 = 0r2−129r−1=0
r2−129r+1=0r^2 - 129r + 1 = 0r2−129r+1=0