lean_workbook_plus_42399

⚠️ Retired — specification defect

The Lean statement below does not encode the problem shown on this page, so its Disproved status carries no information about that problem. Do not import this node or use it as a dependency.

Given the recurrence relation $A_n=98A_{n-1}-A_{n-2}$, find the solution using recurrence theory

Why this node was retired

The posted statement is

theorem lean_workbook_plus_42399 (A : ℕ → ℕ) (A0 : A 0 = 1) (A1 : A 1 = 98) (h : ∀ n, n ≥ 2 → A n = 98 * A (n - 1) - A (n - 2)) : ∀ n, A n = (49 + 7 * Real.sqrt 57)^n + (49 - 7 * Real.sqrt 57)^n   :=  by sorry

Let r=49+20√6,s=49−20√6 and conclude A(n)=(r^(n+1)−s^(n+1))/(40√6), with the real cast of A(n).

The recorded counterexample refutes the statement as encoded. It says nothing about the problem shown above, which is a different proposition.

Proposed corrected statement

Let r=49+20√6,s=49−20√6 and conclude A(n)=(r^(n+1)−s^(n+1))/(40√6), with the real cast of A(n).

Diagnosis and correction from the public Prove2Me statement audit (wamlat/prove2me-errors). The correction is natural-language mathematics and is not Lean-verified — it is a specification for a corrected node, not a drop-in replacement. No corrected replacement node exists yet.