Brown numbers are pairs (m, n) of integers satisfying the condition of Brocard's problem, i.e., such that n! + 1 = m^2 where n! is the factorial and m^2 is a square number. Only three such pairs of numbers are known: (5, 4), (11, 5), (71, 7), and Erdős conjectured that these are the only three such pairs.

Brocard's problem | factorial | square number | Wilson prime