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Posts about Induction

Challenge 5: 5²ⁿ - 2³ⁿ is divisible by 17

Prove in Lean 4 that 5²ⁿ - 2³ⁿ is divisible by 17 for every natural number n.

To do so, complete the following Lean 4 theory:

import Mathlib.Data.Nat.Basic
import Mathlib.Tactic

variable (n : ℕ)

open Nat

example : 17 ∣ 5^(2 * n) - 2^(3 * n) := by
  sorry

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