Given a Fermat Difference Equation (a quadratic Diophantine Equation)

with a Quadratic Surd, assign to each solution the Lagrange number

The product and quotient of two Lagrange numbers are also Lagrange numbers. Furthermore, every Lagrange number is a Power of the smallest Lagrange number with an integral exponent.

**References**

Dörrie, H. *100 Great Problems of Elementary Mathematics: Their History and Solutions.* New York: Dover,
pp. 94-95, 1965.

© 1996-9

1999-05-26