Claims

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1985_02_01_sarkozy: The central binomial coefficient is not squarefree for every sufficiently large n, proved by exponential sums in the Journal of Number Theory (1985) without an explicit threshold.

1995_01_01_velammal: The central binomial coefficient is never squarefree for n greater than 4, proved with Vaughan's identity and exponent pairs in the Hardy-Ramanujan Journal (1995), independently of Granville and Ramaré.

1996_06_01_granville_ramare: The central binomial coefficient is never squarefree for n greater than 4, proved with explicit exponential-sum bounds in Mathematika (1996); the argument has a third-party Lean formalization.

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