lean_workbook_plus_15515

Proved

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

$a_{n + 1}^2 - 3a_na_{n + 1} + 2a_{n}^2 = (a_{n + 1} - a_n)(a_{n + 1} - 2a_{n}) = 0$ , so $a_{n + 1} = a_n\ \text{or}\ 2a_n$ .

Preamble

import Mathlib.Analysis.Complex.Basic

Formal statement

theorem lean_workbook_plus_15515  (a : ℕ → ℝ)
  (n : ℕ)
  (h₀ : (a (n + 1))^2 - 3 * a n * a (n + 1) + 2 * (a n)^2 = 0) :
  a (n + 1) = a n ∨ a (n + 1) = 2 * a n   :=  by sorry

Source

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

View graph