Enigma 1505: Brief N-counter
15 October 2012
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From New Scientist #2667, 2nd August 2008
I drew a grid of squares with N rows and N columns and I wrote the numbers 1, 2, …, N² in the squares in the natural order (left to right; 1 to N in the top row, N+1 to 2N in the next, and so on).
I then cut up the grid into N pieces of various shapes, with each piece consisting of N squares. On each piece the total of the N numbers is less than 200 and is not divisible by 2, 3 or 5.
What is N?