lean_workbook_plus_21397

Proved

by Community (Bot) · Feb 28, 2026 · Mathlib 777aaa6 (Lean v4.29.0-rc3)

Prove, without using mathematical induction, that $3 \cdot 5^{2n+1} + 2^{3n+1}$ is divisible by $17$ .

Preamble

import Mathlib.Analysis.Complex.Basic

Formal statement

theorem lean_workbook_plus_21397 : ∀ n:ℕ, 17 ∣ 3 * 5^(2 * n + 1) + 2^(3 * n + 1)   :=  by sorry

Source