Is the maximum size of a set $A \subseteq {1, \dots, N}$ such that $ab + 1$ is never squarefree (for all $a, b \in A$ ) achieved by taking those $n \equiv 7 (mod 25)$ ?

Worked, still open.

number theory · open · formalized (Lean) · 0 attempts

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vela registry pull vfr_37aec80d874a0239

vela reproduce examples/erdos-problems

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unverified AI candidates (1)

llm-hunter · gpt pro 5.2 · unverified

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

AMS 11 · solved (literature)

theorem erdos_848 : answer(True) ↔ ∀ N, Erdos848For N

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