Brocard's Problem Explorer

Find integer solutions to n! + 1 = m²

About Brocard's Problem

The Problem

Find integer solutions to the equation: n! + 1 = m²

Only three solutions are known: (4,5), (5,11), and (7,71)

Known Solutions

n = 4: 4! + 1 = 24 + 1 = 25 = 5²

n = 5: 5! + 1 = 120 + 1 = 121 = 11²

n = 7: 7! + 1 = 5040 + 1 = 5041 = 71²

The Challenge

No other solutions are known for n < 10⁹. Finding a fourth solution would be a major discovery!

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