I will take a shot at 1.
Subsitute 1 as n.
This gives: \(5^2-1 \times a_2 = -1^1\)
Solving for the unknown, we find \(a_2 = 26\)
Subsituting 2 for n, we get: \(26^2-5a_3=-1^2\)
Solving for the unknown again, we find \(\color{brown}\boxed{a_3=135}\)
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