Prime factors of consecutive-integer products in a prescribed interval

Let n>2k be the least integer for which the product (n−k)⋯(n−1) has no prime factor in (k,2k). Must this least n grow faster than every fixed power of k?

Why it matters and what counts as progress

Why it matters: A superpolynomial lower bound separates this consecutive-product question from the earlier polynomial scale and related binomial-coefficient results.

What counts as progress: Improve the polynomial lower bound to a superpolynomial bound or sharpen the exponential-scale lower estimate.

How the problem developed

  1. 1979 · Open question [1][2]

    Paul Erdős Asked how large the least n>2k can be when the product of k consecutive integers ending at n−1 has no prime factor between k and 2k.

  2. 18 Jun 2026 · Proof [2]

    Wouter van Doorn and Quanyu Tang Confirmed Erdős's superpolynomial-growth conjecture, proving n_k>exp(log²k/(20 log log k)) for all sufficiently large k.

AI contribution

Sources

  1. Paul Erdős, Some Unconventional Problems in Number Theory
  2. Van Doorn and Tang’s prime-factor paper
  3. Conditional Lean formalization
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