The recurrence an=an−1+an−2a_n = a_{n-1} + a_{n-2}an=an−1+an−2 with a1=1,a2=2a_1 = 1, a_2 = 2a1=1,a2=2 produces which sequence?
0, 1, 1, 2, 3, 5, 8, ...
1, 2, 3, 5, 8, 13, 21, ...
Pell: 1, 2, 5, 12, 29, ...
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