Prove2Me

lean_workbook_plus_81452

Proved

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

Prove that dbinomn+13−dbinomn−13=(n−1)2\\dbinom{n+1}{3}-\\dbinom{n-1}{3}=(n-1)^2 .

Preamble
import Mathlib.Analysis.Complex.Basic
Formal statement
theorem lean_workbook_plus_81452 (n : ℕ) : (n + 1).choose 3 - (n - 1).choose 3 = (n - 1)^2   :=  by sorry
Source
https://huggingface.co/datasets/internlm/Lean-Workbook

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