lean_workbook_plus_6007

Proved

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

Let $n=x+19$ \n\n Then: \n\n $n*(n+1)*(n+2)*(n+3) =$ \n\n $=> (n*(n+3))*((n+1)*(n+2))=$ \n\n $=> (n^2+3n)*(n^2+3n+2)=$ \n\n $=> (n^2+3n)^2+ 2*(n^2+3n)=$ \n\n $=> (n^2+3n)^2+2*(n^2+3n)+1-1 =$ \n\n $=> (n^2+3n+1)^2 - 1$

Preamble

import Mathlib.Analysis.Complex.Basic

Formal statement

theorem lean_workbook_plus_6007  (x : ℕ)
  (n : ℕ)
  (h₀ : n = x + 19) :
  n * (n + 1) * (n + 2) * (n + 3) = (n^2 + 3 * n + 1)^2 - 1   :=  by sorry

Source

https://huggingface.co/datasets/internlm/Lean-Workbook

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