January 1st, 2017, 08:24 AM  #1 
Newbie Joined: Dec 2016 From: New Jersey Posts: 7 Thanks: 1  Math Problem Requiring Thinking
A kcity is a k by k grid of positive integers so that every integer greater than 1 is the sum of one integer from the same row and one integer from the same column. Below is an example of a 3city: 1 1 2 2 3 1 6 4 1 Make a 5city that has an integer that is greater than or equal to 150. 
January 1st, 2017, 10:20 AM  #2 
Senior Member Joined: Sep 2015 From: CA Posts: 893 Thanks: 479 
you've posted this 3 times now. I looked at it for a bit, didn't make any progress. I imagine others have done the same. Sometimes we don't have the answers. 
January 1st, 2017, 06:07 PM  #3 
Newbie Joined: Dec 2016 From: New Jersey Posts: 7 Thanks: 1 
Sorry. I thought that the algorithm of the website might have pushed the thread to the bottom where many people wouldn't see it. Won't happen again.

January 2nd, 2017, 09:55 AM  #4 
Senior Member Joined: Mar 2015 From: New Jersey Posts: 905 Thanks: 72 
This is the way I would set it up (think about it): Let $\displaystyle a_{ij}$ be a typical grid element. Then $\displaystyle a_{ij}=a_{ik}+a_{mj}, \ k\neq i, m\neq j$ 

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