Pell.m

Pell(d,s,n) returns the first n positive integer solution to the modified Pell's equation x^2-dy^2=+

For integers d and s with d nonsquare and positive, Pell(d,s,n) returns the first n positive integer solution (x,y) to the modified Pell's equation x^2-dy^2=(-1)^s, if such a solution exists. Such a solution always exists if s is even, i.e. if the right side is equal to 1, though a solution may not exist if the right side is -1 (s odd), in which case a message is given indicating that this is so. QCF.m is required to run this program.