refine' (Nat.dvd_add_right h_m_prod).mp _
k n : ℕ
h : k < n
m : ℕ := (F n).gcd (F k)
h_n : m ∣ F n
h_k : m ∣ F k
h_m_prod : m ∣ ∏ k ∈ range n, F k
h_prod : ∏ k ∈ range n, F k + 2 = F n
⊢ m ∣ 2
k n : ℕ
h : k < n
m : ℕ := (F n).gcd (F k)
h_n : m ∣ F n
h_k : m ∣ F k
h_m_prod : m ∣ ∏ k ∈ range n, F k
h_prod : ∏ k ∈ range n, F k + 2 = F n
⊢ m ∣ ∏ k ∈ range n, F k + 2