ring_nf
case succ
n : ℕ
hn : ∏ k ∈ range n, F k = F n - 2
⊢ (2 ^ 2 ^ n) ^ 2 - 1 ^ 2 = 2 ^ 2 ^ (n + 1) + 1 - 2
case succ
n : ℕ
hn : ∏ k ∈ range n, F k = F n - 2
⊢ 2 ^ (2 ^ n * 2) - 1 = 1 + 2 ^ (2 ^ n * 2) - 2