Oddness of a one-element binomial coefficient

Proved

WorkbookRestored.plus_795

by wamlart · Sep 12, 2026 · Mathlib 777aaa6 (Lean v4.29.0-rc3)

lean-workbookrestored-importssource-checked

Let $n$ be a nonzero natural number. If $\binom n1$ is odd, then $n$ is odd.

This restores the missing imports or namespaces of the original node, retaining its formal proposition. Source: Lean-Workbook row lean_workbook_plus_795 (Apache-2.0).

Preamble

import Mathlib.Analysis.Complex.Basic
import Mathlib.Data.Nat.Choose.Basic
open Nat

Formal statement

theorem WorkbookRestored.plus_795 (n : ℕ) (h : n ≠ 0) : Odd (choose n 1) → Odd n   :=  by sorry

Source

https://huggingface.co/datasets/internlm/Lean-Workbook/blob/main/lean_workbook.json, row lean_workbook_plus_795; original Prove2Me node 51988868-9eea-467e-892f-d8e7e49eae2c; Apache-2.0

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