Brown numbers are pairs integers satisfying the
condition of Brocard's problem , i.e., such that
where factorial and 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 .
See also Brocard's Problem ,
Factorial ,
Square Number ,
Wilson
Prime
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References Guy, R. K. Unsolved Problems in Number Theory, 2nd ed. Pickover, C. A. Keys
to Infinity. Referenced on
Wolfram|Alpha Brown Numbers
Cite this as:
Weisstein, Eric W. "Brown Numbers." From
MathWorld https://mathworld.wolfram.com/BrownNumbers.html
Subject classifications
of integers satisfying the
condition of Brocard's problem, i.e., such that
is the factorial and 
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.
