A recurrence has the form $a_n = c_1 a_{n-1} + c_2 a_{n-2}$ for unknown constants $c_1, c_2$. Given the sequence values $a_0 = 1, a_1 = 2, a_2 = 5, a_3 = 12$, which pair $(c_1, c_2)$ is consistent with all four values?