Which condition makes a recurrence an=c1an−1+c2an−2a_n = c_1 a_{n-1} + c_2 a_{n-2}an=c1an−1+c2an−2 'homogeneous'?
No external term f(n)f(n)f(n) is added.
The coefficients c1,c2c_1, c_2c1,c2 are equal.
The sequence is constant.
The roots of the characteristic equation are real.