# [seqfan] Re: Overview of sequence arising from binary quadratic forms

Charles Greathouse charles.greathouse at case.edu
Sat Jun 28 20:25:18 CEST 2014

```I think Peter's definition disallows (0, 0), not just (x, 0) and (0, y).
(Or am I mistaken?)

Charles Greathouse
Analyst/Programmer
Case Western Reserve University

On Sat, Jun 28, 2014 at 1:34 PM, Neil Sloane <njasloane at gmail.com> wrote:

> Peter said: "Since it calculates positive numbers represented by a binary
> quadratic form it does no matter what definition you follow."
>
> I really don't think the definition you are using is the right one,
> and I think it does make a difference.
>
> Take the quadratic form 2x^2+y^2. According to your definition, this does
> not
> represent 1. That is simply wrong. The numbers represented by this form are
> given by A002479: 0, 1, 2, 3, 4, 6, 8, 9, 11, 12, 16, 17, 18, 19, 22, 24,
> 25, 27, 32, 33, 34, 36,  ...
>
> My Quadratic Forms page now mentions your "satellite page" in two places.
> But I really wish you would use
> the right definition (meaning the naive definition) of "represent".
>
> Neil
>
>
> On Sat, Jun 28, 2014 at 9:24 AM, Peter Luschny <peter.luschny at gmail.com>
> wrote:
>
> > As a satellite to the Wiki page of Neil I've written a small program
> > that will handle the different cases under a single interface.
> >
> > It is written in Sage/Python and based for the indefinite quadratic
> > forms on a program by Will Jagy.
> >
> > Suggestions for improvements and extensions are welcome. Please report
> > bugs to me immediately.
> >
> > Peter
> >
> > P.S.  Since it calculates positive numbers represented by a binary
> > quadratic form it does no matter what definition you follow.
> >
> >
> > _______________________________________________
> >
> > Seqfan Mailing list - http://list.seqfan.eu/
> >
>
>
>
> --
> Dear Friends, I have now retired from AT&T. New coordinates:
>
> Neil J. A. Sloane, President, OEIS Foundation
> 11 South Adelaide Avenue, Highland Park, NJ 08904, USA.
> Also Visiting Scientist, Math. Dept., Rutgers University, Piscataway, NJ.