rw [Finset.prod_const, Finset.card_range, ← pow_mul]
k n : ℕ
hk : k > 0
h : ↑k ! = ∏ i ∈ Finset.range n, (2 ^ n - 2 ^ i)
h2 : ∑ i ∈ Finset.range n, i < k
hn : 6 ≤ n
⊢ ∏ __ ∈ Finset.range n, 2 ^ n = 2 ^ (n * n)
no goals