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View Full Version : OT - Another prime square puzzle


Brillig
03-25-2003, 04:19 PM
This week's challenge: arrange the numbers 1 to 9 in a 3x3 matrix. Reading the matrix in any direction as 3-digit numbers (i.e. up/down, right/left or in either direction on the main diagonals), each of the numbers 1 to 9 must be used at least once in a 3-digit prime number.

Your score is the total number of 3-digit prime numbers in your 3x3 matrix. (There are 16 possible 3 digit numbers, but for obvious reasons, a score of 16 is impossible).

My best score so far is 8 - can you do better?

John Galt
03-25-2003, 05:00 PM
I think I have one with 9 and I can't figure out a way to get more:

7 6 9
5 4 8
1 2 3

Brillig
03-25-2003, 05:02 PM
Hmm, I see a problem with your grid - the number 2.

None of

642
246
123
321

are prime...

Each number has to be used at least once in a 3-digit prime, sorry if the instructions are confusing....

John Galt
03-25-2003, 05:04 PM
Damn it, I thought I finally got one of these stinkin puzzles.