Possible misformalizations II

## Purpose

This is a follow-up to #4896. I found several more statements that appear to
be provable without answering the intended mathematical question.

These may be misformalizations, so I am collecting them here for review.

Each checkbox below is one independently trackable item. A dedicated issue or
PR can be linked on the same line and the item checked once resolved.

## Exact self-answers

- [ ] [Erdős 33](https://github.com/google-deepmind/formal-conjectures/blob/main/FormalConjectures/ErdosProblems/33.lean)
— **Problem:** the entire unknown infimum/limsup expression can be copied into
`answer`, so the theorem closes by `rfl`. **Likely fix:** require a concrete
value or formula independent of the target expression.

- [ ] [Erdős 329](https://github.com/google-deepmind/formal-conjectures/blob/main/FormalConjectures/ErdosProblems/329.lean)
— **Problem:** the unknown supremum can be copied into `answer`, so the theorem
closes by `rfl`. **Likely fix:** require a concrete value independent of that
supremum.

- [ ] [Erdős 348](https://github.com/google-deepmind/formal-conjectures/blob/main/FormalConjectures/ErdosProblems/348.lean)
— **Problem:** the target set of pairs can be copied into `answer`, so the
theorem closes by `rfl`. **Likely fix:** state the proposed set explicitly,
independently of the target set-builder expression.

- [ ] [Erdős 409, part iii](https://github.com/google-deepmind/formal-conjectures/blob/main/FormalConjectures/ErdosProblems/409.lean)
— **Problem:** the unknown density `α` is already a theorem parameter and can
be returned as `answer(α)` by `rfl`. **Likely fix:** if the source predicts a
concrete density, state it directly; otherwise remove the misleading open
`answer` slot.

## Reflexive asymptotic answers

- [ ] [Erdős 422 `growth_rate`](https://github.com/google-deepmind/formal-conjectures/blob/main/FormalConjectures/ErdosProblems/422.lean)
— **Problem:** the target function itself can be used as the Big-O answer;
`isBigO_refl` then closes the theorem. **Likely fix:** require an independently
specified comparison scale or restrict the permitted answer family.

- [ ] [Erdős 539](https://github.com/google-deepmind/formal-conjectures/blob/main/FormalConjectures/ErdosProblems/539.lean)
— **Problem:** `cofactorThreshold` itself can be used as its Big-Theta answer;
`isTheta_refl` closes the theorem. **Likely fix:** require an independently
specified asymptotic formula or comparison family.

- [ ] [Erdős 789](https://github.com/google-deepmind/formal-conjectures/blob/main/FormalConjectures/ErdosProblems/789.lean)
— **Problem:** `subsetSumThreshold` itself can be used as its Big-Theta answer;
`isTheta_refl` closes the theorem. **Likely fix:** require an independently
specified asymptotic formula or comparison family.

## Degenerate witness

- [ ] [OEIS A211417 `general_divisibility`](https://github.com/google-deepmind/formal-conjectures/blob/main/FormalConjectures/OEIS/211417.lean)
— **Problem:** `D = 0` makes the current existential vacuous. **Update:** the intended version appears true with the explicit positive witness `D(r) = lcm(1,...,r)^|{1 ≤ i ≤ r : gcd(i,30)=1}|`. **Likely fix:** state this witness, or require `D > 0`. The general proof is paper-complete but not yet Lean-checked; the four fixed statements are separate in #5010.

## Incorrect boundary and indexing

- [ ] [OEIS A111291](https://github.com/google-deepmind/formal-conjectures/blob/main/FormalConjectures/OEIS/111291.lean)
— **Problem:** every `1 < x < 2` is a counterexample: `countRefactorable x = 1`, but `x/(2*log x) > 1`.
**Likely fix:** use an eventual or explicitly sufficiently-large bound.

- [ ] [OEIS A109074](https://github.com/google-deepmind/formal-conjectures/blob/main/FormalConjectures/OEIS/109074.lean)
— **Problem:** `n = 1` gives `frac 1 = 1` but `b 2 / b 1 = 3`. Also, the helper `b` is the ternary Fuss–Catalan sequence, not A005156.
**Likely fix:** define the actual A005156 and use the data-compatible shift `A005156(n)/A005156(n-1)`.

## Related tracking

- #4892 — Erdős 319
- #4919 — Erdős 688
- #4922 — Erdős 142

## Caveat

This list was organized with AI assistance from my long working notes and may
contain transcription or interpretation errors.

Start with the linked Lean files under FormalConjectures/ErdosProblems and FormalConjectures/OEIS, checking each statement and its proof for the listed self-answer, reflexive, vacuous, boundary, or indexing issue. Compare the formal statement with the intended mathematical claim and verify that each correction compiles without closing trivially; completion is tracked by checking the relevant item or linking a dedicated issue or PR.

Written by the indexing model from the issue text.