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Re: How many rectangles are in an n by n square array of dots?
Posted:
Sep 9, 2006 6:54 PM


On 9/9/06, Oliver Stemforn <olive79pop@yahoo.com> wrote: > To: > > Lou Talman > Department of Mathematical and Computer Sciences > Metropolitan State College of Denver > > > You are wrong about me having to be more careful when a rectangle counts. In the description for this problem, I never limited the orientation of the rectangles I was seeking to be counted within an array. I stated to get a count for the total. If I had only wanted a total of vertical/horizontal rectangles, I would have had to mention that explicitly. Or if I had wanted only a total of oblique rectangles, I would have had to mention that explicitly. >
The original question was: >Can you come up with a polynomial in terms of n for the total number of rectangles for a general n by n array?
I think the implication is that if you wanted a polynomial, you should have been more careful in your choice of problem.
See http://www.research.att.com/~njas/sequences/A085582 for example. Joshua Zucker



