induction n using recBase2
n : Nat
h : n > 0
⊢ 2 ^ log2' n ≤ n
case zero
h : 0 > 0
⊢ 2 ^ log2' 0 ≤ 0

case one
h : 1 > 0
⊢ 2 ^ log2' 1 ≤ 1

case div2
n✝ : Nat
a✝ : n✝ / 2 + 1 > 0 → 2 ^ log2' (n✝ / 2 + 1) ≤ n✝ / 2 + 1
h : n✝ + 2 > 0
⊢ 2 ^ log2' (n✝ + 2) ≤ n✝ + 2