PDF chapter test TRY NOW

If a_1 = 1 and a_2 = 1 and a_n = 2a_{n - a} + a_{n - 2}, n \ge 3, n \in \mathbb{N}, then find the first six terms of the sequence.
 
a_1=
 
a_2 =
 
a_3 =
 
a_4=
 
a_5=
 
a_6=