The sequence 1,2,7,20,61,…1, 2, 7, 20, 61, \ldots1,2,7,20,61,… satisfies the linear recurrence an=c1an−1+c2an−2a_n = c_1 a_{n-1} + c_2 a_{n-2}an=c1an−1+c2an−2. Find c1+c2c_1 + c_2c1+c2.
333
444
555
666