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Looking for a square result (Posted on 2018-06-14) Difficulty: 3 of 5
For each positive integer n, let Mn be the square matrix (nxn) where each diagonal entry is 2018, and every other entry is 1.

Determine the smallest positive integer n (if any) for which the value
of det(Mn) is a perfect square.

No Solution Yet Submitted by Ady TZIDON    
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Comments: ( Back to comment list | You must be logged in to post comments.)
re: n = 4 is a square, regardless of | Comment 11 of 18 |
(In reply to n = 4 is a square, regardless of "d" by Steven Lord)

am I missing something?  Check this link


http://www.wolframalpha.com/input/?i=Det%5B%7B%7Bx,1,1,1%7D,%7B1,x,1,1%7D,%7B1,1,x,1%7D,%7B1,1,1,x%7D%7D%5D



it would seem to suggest your formulas are off.  If my understanding is correct then I think a general formula would be


(d-1)^(n-1)*(d+n-1)

  Posted by Daniel on 2018-06-15 12:18:31
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