[seqfan] Finding numbers represented by indefinite binary quadratic forms

[Neil Sloane]

Does anyone have a program for doing the following:

Given an indefinite binary quadratic form ax^2+bxy+cy^2 (with discriminant
b^2-4ac>0 and not a square) and a positive or negative number n, decide if
ax^2+bxy+cy^2 = n has a solution.

(If n = p is a prime, one can use the PARI command qfbsolve(Qfb(a,b,c),p) )

Neil