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	<title>Comments on: Perplex City and Magic Squares</title>
	<atom:link href="http://quasistoic.org/ts/archives/2006/08/13/magic-square-solver/feed/" rel="self" type="application/rss+xml" />
	<link>http://quasistoic.org/ts/archives/2006/08/13/magic-square-solver/</link>
	<description>but still a permanent idiot</description>
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		<item>
		<title>By: SÃ¸ren Blaabjerg</title>
		<link>http://quasistoic.org/ts/archives/2006/08/13/magic-square-solver/comment-page-1/#comment-3097</link>
		<dc:creator>SÃ¸ren Blaabjerg</dc:creator>
		<pubDate>Thu, 13 Aug 2009 19:22:44 +0000</pubDate>
		<guid isPermaLink="false">http://quasistoic.org/ts/archives/2006/08/13/magic-square-solver/#comment-3097</guid>
		<description>Dear Danny

I have studied your list a bit further and found quite a number of omissions and duplicates
as well. In the end I decided to write a small computer program myself in order to find the complete list, and I have just succeeded doing so. As expected the conclusion was, that there are indeed all in all 880 unique solutions or 880 x 8 solutions if you count all rotations and reflexions. I made the program in such a way, that you can choose either and step through all the solutions displayed one by one.

Most of the solutions are not particularly interesting though. For instance I find those, where both the 2 x 2 subsquares at the corners and the subsquare at the center add up to the same sum as the rows, columns and two diagonals particularly pleasing. There are quite a number of those, around 350 unique ones I believe.</description>
		<content:encoded><![CDATA[<p>Dear Danny</p>
<p>I have studied your list a bit further and found quite a number of omissions and duplicates<br />
as well. In the end I decided to write a small computer program myself in order to find the complete list, and I have just succeeded doing so. As expected the conclusion was, that there are indeed all in all 880 unique solutions or 880 x 8 solutions if you count all rotations and reflexions. I made the program in such a way, that you can choose either and step through all the solutions displayed one by one.</p>
<p>Most of the solutions are not particularly interesting though. For instance I find those, where both the 2 x 2 subsquares at the corners and the subsquare at the center add up to the same sum as the rows, columns and two diagonals particularly pleasing. There are quite a number of those, around 350 unique ones I believe.</p>
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	<item>
		<title>By: Lawid</title>
		<link>http://quasistoic.org/ts/archives/2006/08/13/magic-square-solver/comment-page-1/#comment-3096</link>
		<dc:creator>Lawid</dc:creator>
		<pubDate>Mon, 10 Aug 2009 11:02:54 +0000</pubDate>
		<guid isPermaLink="false">http://quasistoic.org/ts/archives/2006/08/13/magic-square-solver/#comment-3096</guid>
		<description>Hi,

I have set of 100 integers organized in 10*10 table. Only the sums of two rows are different by +1 and -1 compared to the sum required for the magic square. Can you help me in checking if we can get with these numbers a magic square table?  

Thanks</description>
		<content:encoded><![CDATA[<p>Hi,</p>
<p>I have set of 100 integers organized in 10*10 table. Only the sums of two rows are different by +1 and -1 compared to the sum required for the magic square. Can you help me in checking if we can get with these numbers a magic square table?  </p>
<p>Thanks</p>
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	</item>
	<item>
		<title>By: SÃ¸ren Blaabjerg</title>
		<link>http://quasistoic.org/ts/archives/2006/08/13/magic-square-solver/comment-page-1/#comment-3095</link>
		<dc:creator>SÃ¸ren Blaabjerg</dc:creator>
		<pubDate>Sat, 01 Aug 2009 10:49:18 +0000</pubDate>
		<guid isPermaLink="false">http://quasistoic.org/ts/archives/2006/08/13/magic-square-solver/#comment-3095</guid>
		<description>Dear Danny

I have just studied your list further and can confirm, that your list is far from  comprehensive and indeed also contain quite a number of duplications (i.e. solutions that can be derived through reflexion and/or rotation of other solutions on the list). I you are interested, I might myself have a look on your code :-)</description>
		<content:encoded><![CDATA[<p>Dear Danny</p>
<p>I have just studied your list further and can confirm, that your list is far from  comprehensive and indeed also contain quite a number of duplications (i.e. solutions that can be derived through reflexion and/or rotation of other solutions on the list). I you are interested, I might myself have a look on your code :-)</p>
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	</item>
	<item>
		<title>By: Danny Dawson</title>
		<link>http://quasistoic.org/ts/archives/2006/08/13/magic-square-solver/comment-page-1/#comment-3094</link>
		<dc:creator>Danny Dawson</dc:creator>
		<pubDate>Wed, 29 Jul 2009 17:05:45 +0000</pubDate>
		<guid isPermaLink="false">http://quasistoic.org/ts/archives/2006/08/13/magic-square-solver/#comment-3094</guid>
		<description>The 924 solutions I listed are indeed unique, but not rotationally or reflexively so.

Also, as several commenters have pointed out, it seems that my list is not comprehensive. I haven&#039;t taken the time yet to look back at my old code and determine why this is so, but at some point, I certainly should do so.

Thanks to all of you for your comments, and especially to SÃ¸ren for continuing to work on this puzzle. Even though I haven&#039;t done any work on this myself in a long time, it&#039;s still quite fun to think about. :)</description>
		<content:encoded><![CDATA[<p>The 924 solutions I listed are indeed unique, but not rotationally or reflexively so.</p>
<p>Also, as several commenters have pointed out, it seems that my list is not comprehensive. I haven&#8217;t taken the time yet to look back at my old code and determine why this is so, but at some point, I certainly should do so.</p>
<p>Thanks to all of you for your comments, and especially to SÃ¸ren for continuing to work on this puzzle. Even though I haven&#8217;t done any work on this myself in a long time, it&#8217;s still quite fun to think about. :)</p>
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		<title>By: SÃ¸ren Blaabjerg</title>
		<link>http://quasistoic.org/ts/archives/2006/08/13/magic-square-solver/comment-page-1/#comment-3093</link>
		<dc:creator>SÃ¸ren Blaabjerg</dc:creator>
		<pubDate>Wed, 29 Jul 2009 15:52:05 +0000</pubDate>
		<guid isPermaLink="false">http://quasistoic.org/ts/archives/2006/08/13/magic-square-solver/#comment-3093</guid>
		<description>In the above comment I by mistake read the numbers underneath instead of the numbers above. Sorry? However I have just discovered another example of duplication. Please take a look at solution #30 and then solution #37!</description>
		<content:encoded><![CDATA[<p>In the above comment I by mistake read the numbers underneath instead of the numbers above. Sorry? However I have just discovered another example of duplication. Please take a look at solution #30 and then solution #37!</p>
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	</item>
	<item>
		<title>By: SÃ¸ren Blaabjerg</title>
		<link>http://quasistoic.org/ts/archives/2006/08/13/magic-square-solver/comment-page-1/#comment-3092</link>
		<dc:creator>SÃ¸ren Blaabjerg</dc:creator>
		<pubDate>Wed, 29 Jul 2009 14:27:48 +0000</pubDate>
		<guid isPermaLink="false">http://quasistoic.org/ts/archives/2006/08/13/magic-square-solver/#comment-3092</guid>
		<description>Since my comment above, I have myself found a lot more unique magic squares. I have not yet checked, if all of them are on your list. They might well be.

By the way, I have found, that on your otherwise quite impresive complete list of 4x4 magic square solutions there are in fact repetitions (assuming of course, that magic squares, that can be derived from other magic squares by mirroring and rotation are only counted first time, they occur). At least I have found, that solution  

#388:                   is in fact identical to solution            #120:

14    1    8   11                                                            7    6   10   11
15    4    5   10                                                          12    9     5     8
  3  16    9     6                                                          13  16     4     1 
  2  13  12     7                                                            2    3   15   14</description>
		<content:encoded><![CDATA[<p>Since my comment above, I have myself found a lot more unique magic squares. I have not yet checked, if all of them are on your list. They might well be.</p>
<p>By the way, I have found, that on your otherwise quite impresive complete list of 4&#215;4 magic square solutions there are in fact repetitions (assuming of course, that magic squares, that can be derived from other magic squares by mirroring and rotation are only counted first time, they occur). At least I have found, that solution  </p>
<p>#388:                   is in fact identical to solution            #120:</p>
<p>14    1    8   11                                                            7    6   10   11<br />
15    4    5   10                                                          12    9     5     8<br />
  3  16    9     6                                                          13  16     4     1<br />
  2  13  12     7                                                            2    3   15   14</p>
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	<item>
		<title>By: Jhansi</title>
		<link>http://quasistoic.org/ts/archives/2006/08/13/magic-square-solver/comment-page-1/#comment-3091</link>
		<dc:creator>Jhansi</dc:creator>
		<pubDate>Thu, 23 Jul 2009 19:05:44 +0000</pubDate>
		<guid isPermaLink="false">http://quasistoic.org/ts/archives/2006/08/13/magic-square-solver/#comment-3091</guid>
		<description>hi i found one more solution which is not available in your list of solutions..

1 14 13 4
12 6 7 9
8 10 11 5
13 3 2 16

Thanks,
Jhansi.</description>
		<content:encoded><![CDATA[<p>hi i found one more solution which is not available in your list of solutions..</p>
<p>1 14 13 4<br />
12 6 7 9<br />
8 10 11 5<br />
13 3 2 16</p>
<p>Thanks,<br />
Jhansi.</p>
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	<item>
		<title>By: SÃ¸ren Blaabjerg</title>
		<link>http://quasistoic.org/ts/archives/2006/08/13/magic-square-solver/comment-page-1/#comment-3090</link>
		<dc:creator>SÃ¸ren Blaabjerg</dc:creator>
		<pubDate>Tue, 16 Jun 2009 08:20:40 +0000</pubDate>
		<guid isPermaLink="false">http://quasistoic.org/ts/archives/2006/08/13/magic-square-solver/#comment-3090</guid>
		<description>I believe, that I myself (not using any formulas or with help of a computer) to have found (so far) no less than 1248 unique &quot;perfect&quot;  4x4 magic squares. The number of unique sets of 8 magic squares, where all the variants can be derived from each other by mirroring and rotation I have found to be 156. (156 x 8=1248)

By perfect 4x4 magic squares I mean squeres where not only do both of the diagonals add up to 34, but so do the numbers in each of the small 2x2 squares at each of the corners, the central 2x2 square, and the sums of the 2 numbers in the middle of the top and the bottom row as well as the sums of the 2 numbers in the middle of the leftmost and rightmost columns.

By the way, I am thinking of writing a small book displaying all of these solution (not dwelving into theories and methods though because it is meant primarily for enjoyment. Do you think, that might have any interest?</description>
		<content:encoded><![CDATA[<p>I believe, that I myself (not using any formulas or with help of a computer) to have found (so far) no less than 1248 unique &#8220;perfect&#8221;  4&#215;4 magic squares. The number of unique sets of 8 magic squares, where all the variants can be derived from each other by mirroring and rotation I have found to be 156. (156 x 8=1248)</p>
<p>By perfect 4&#215;4 magic squares I mean squeres where not only do both of the diagonals add up to 34, but so do the numbers in each of the small 2&#215;2 squares at each of the corners, the central 2&#215;2 square, and the sums of the 2 numbers in the middle of the top and the bottom row as well as the sums of the 2 numbers in the middle of the leftmost and rightmost columns.</p>
<p>By the way, I am thinking of writing a small book displaying all of these solution (not dwelving into theories and methods though because it is meant primarily for enjoyment. Do you think, that might have any interest?</p>
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	<item>
		<title>By: joshua meadows</title>
		<link>http://quasistoic.org/ts/archives/2006/08/13/magic-square-solver/comment-page-1/#comment-3087</link>
		<dc:creator>joshua meadows</dc:creator>
		<pubDate>Wed, 18 Mar 2009 01:37:58 +0000</pubDate>
		<guid isPermaLink="false">http://quasistoic.org/ts/archives/2006/08/13/magic-square-solver/#comment-3087</guid>
		<description>I found one you missed
1st row: 1,15,14,4
2nd row: 12,6,7,9
3rd row: 8,10,11,5
4th row: 13,3,12,16
Thanks though, i like what your doing with this.</description>
		<content:encoded><![CDATA[<p>I found one you missed<br />
1st row: 1,15,14,4<br />
2nd row: 12,6,7,9<br />
3rd row: 8,10,11,5<br />
4th row: 13,3,12,16<br />
Thanks though, i like what your doing with this.</p>
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	<item>
		<title>By: Chandrashekhar Joshi</title>
		<link>http://quasistoic.org/ts/archives/2006/08/13/magic-square-solver/comment-page-1/#comment-3085</link>
		<dc:creator>Chandrashekhar Joshi</dc:creator>
		<pubDate>Thu, 01 Jan 2009 15:15:31 +0000</pubDate>
		<guid isPermaLink="false">http://quasistoic.org/ts/archives/2006/08/13/magic-square-solver/#comment-3085</guid>
		<description>Hi:
I was checking a magic square with following conditions:
x   x   x   10
x   x   9   x
x   8   x   x
7   x   x   x
However I did not get any sucess using the formula given by you. Is there any solution which exists using this combination?</description>
		<content:encoded><![CDATA[<p>Hi:<br />
I was checking a magic square with following conditions:<br />
x   x   x   10<br />
x   x   9   x<br />
x   8   x   x<br />
7   x   x   x<br />
However I did not get any sucess using the formula given by you. Is there any solution which exists using this combination?</p>
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