conv => rhs; rw [two_mul, pow_add]
case odd_prime
n : ℕ
hp : Nat.Prime (Nat.succ (2 * n))
hi : ∀ (x : ℕ), x ≤ 2 * n → prodPrimes x ≤ 4 ^ Nat.pred x
⊢ prodPrimes (Nat.succ (2 * n)) ≤ 4 ^ (2 * n)
case odd_prime
n : ℕ
hp : Nat.Prime (Nat.succ (2 * n))
hi : ∀ (x : ℕ), x ≤ 2 * n → prodPrimes x ≤ 4 ^ Nat.pred x
⊢ prodPrimes (Nat.succ (2 * n)) ≤ 4 ^ n * 4 ^ n