rw [log2'_div2]
n : Nat
h_ind : n / 2 + 1 > 0 → 2 ^ log2' (n / 2 + 1) ≤ n / 2 + 1
h : n + 2 > 0
⊢ 2 ^ log2' (n + 2) ≤ n + 2
n : Nat
h_ind : n / 2 + 1 > 0 → 2 ^ log2' (n / 2 + 1) ≤ n / 2 + 1
h : n + 2 > 0
⊢ 2 ^ (log2' (n / 2 + 1) + 1) ≤ n + 2