lean_workbook_plus_45672

Proved

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

Obtain that $5^4 \equiv 1 \pmod{16}$ . So if $n=4k+x$ , then $5^n \equiv 5^x \pmod{16}$ , where $x \in \{0,1,2,3\}$ .

Preamble

import Mathlib.Analysis.Complex.Basic

Formal statement

theorem lean_workbook_plus_45672 : 5 ^ 4 ≡ 1 [ZMOD 16]   :=  by sorry

Source