Let $A \subseteq N$ be an infinite set. Is $n \in A \sum \frac{1}{2 ^{n} - 1}$ irrational?

Worked, still open.

irrationality · open · formalized (Lean) · 0 attempts

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unverified AI candidates (2)

gpt-erdos · GPT-5.2 Pro + Deep Research · unverified

No one currently knows the answer in full generality.

llm-hunter · gpt pro 5.2 · unverified

1 LLM attack(s) recorded (gpt pro 5.2); unverified.

AMS 11 · open (literature)

theorem erdos_257 : answer(sorry) ↔ ∀ (A : Set ℕ), A.Infinite →
    Irrational (∑' n : A, (1 : ℝ) / (2 ^ n.1 - 1))

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