Re: What am I doing wrong?

[Bill Allombert <Bill.Allombert@math.u-bordeaux.fr>]

On Fri, May 20, 2016 at 01:59:14PM +0200, Dirk Laurie wrote:
> % qfbsolve(Qfb(1,0,-5),4)
> %2 = 0
> 
> Why are the solutions x=3,y=1; x=7,y=3; x=18,y=8; etc not found?

Because 4 is not prime:

? ?qfbsolve
qfbsolve(Q,p): Return [x,y] so that Q(x,y)=p where Q is a binary
quadratic form and p a prime
number, or 0 if there is no solution.

Cheers,
Bill.