The prize is named after D. Andrew "Andy" Beal, a Dallas banker and number theory enthusiast, who provided the money. The society, headquartered in Providence, R.I., announced the increase to $1 million Monday.
Beal's Conjecture is that the only solutions to the equation Ax + By = Cz, when A, B, C, are positive integers, and x, y, and z are positive integers greater than 2, are those in which A, B, and C have a common factor.
The conjecture implies Fermat's Last Theorem, which was proved in the 1990s, 300 years after Fermat said he had a proof and then died without revealing it.
The Beal Prize will be awarded for a proof of the conjecture or a counter-example that disproves it. Possible winners should not be submitted to Beal or to the society but should be published in a refereed journal.
The committee will wait two years before deciding whether a possible winner deserves the prize.