Which condition must be met for a recurrence an=f(an−1,an−2,… )a_n = f(a_{n-1}, a_{n-2}, \dots)an=f(an−1,an−2,…) to be classified as linear?
All terms aia_iai must be raised to the power of 1
The coefficients must be constant
The sequence must converge
The recurrence must have a closed-form solution