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Old 2006-03-18, 22:14   #1
Citrix
 
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Default Concordant Form

http://mathworld.wolfram.com/ConcordantForm.html

According to this page 60 is a concordant number but I can't find any solutions, could some one please help me find a solution.I personally think this is an error.

Thanks,Citrix

Last fiddled with by Citrix on 2006-03-18 at 22:15
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Old 2006-03-19, 01:33   #2
grandpascorpion
 
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Default Googled it

http://134.129.111.8/cgi-bin/wa.exe?...thry&O=A&P=329
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Old 2006-03-19, 01:56   #3
Citrix
 
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It does not provide a solution for 60? I am not sure what to do with the link?

Citrix
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Old 2006-03-19, 01:58   #4
jchein1
 
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Hi Citrix,

The first two solutions is given by

(x,y) = (187,84)
(x,y) = (748,336).


cheers,


Joesph E.Z. Chein
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Old 2006-03-19, 02:07   #5
Citrix
 
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Thanks, my program was too slow to find one? Can your program find a solution for 103? (This is an open problem)

Citrix
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Old 2006-03-19, 05:26   #6
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Sorry, I thought you needed more info on this worked.

103 isn't solvable (if the Birch-Swinnerton-Dyer conjecture is valid)
http://www.mathpages.com/home/286tab1.htm
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Old 2006-03-19, 11:49   #7
mfgoode
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Quote:
Originally Posted by jchein1
Hi Citrix,

The first two solutions is given by

(x,y) = (187,84)
(x,y) = (748,336).


cheers,


Joesph E.Z. Chein
:surprised Fantastic Joe, Keep up the good work.
Maybe you should have added N=60 for those following this thread.
Mally
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Old 2006-03-19, 15:33   #8
jchein1
 
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Hi Citrix and mfgoode,


If one put a = x^2 – y^2 and b = 2xy into the concordance form 103, you would have

x^4 + 410*x^2*y^2 + y^4 = d^2 (1).

The necessary condition for that equation to be solvable is that

5 | x or 5 | y.

It appears that there may be no solutions for x, y <= 100000 (my program still cooking but almost done). The general solution for equation (1) (either has infinitely solutions or no solutions) depends upon the algebraic number theory and is connected with the units in certain algebraic number fields.

cheers,


Joseph E.Z. Chein
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Old 2006-03-19, 20:45   #9
Citrix
 
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I have reduced the problem to this simple equation

if (103*r*r+k*r)/(k*r+k*k)=(a/b)^2
Then only is there a solution to the 103 case.

Clearly r and k must not have a common factor ie. they must be coprime, this eliminates alot of steps.

There are other rules you can develop and eliminate some steps.

Ultimately it comes to this
(103*r*r+k*r)=a^2
and (k*r+k*k)=b^2

Which is equally difficult to solve. So no real progress here.
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