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Topic: One Through Nine, With Eight Missing, And Two Ones
Replies: 19   Last Post: Mar 31, 2011 5:11 PM

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 Dan Hoey Posts: 172 Registered: 12/6/04
Re: One Through Nine, With Eight Missing, And Two Ones
Posted: Mar 24, 2011 9:12 PM

On 3/24/2011 1:37 PM, Leroy Quet wrote:
> The solution -- except reflections and rotations -- can be seen to be
> unique by first noting that, due to the evenness and oddness of the
> numbers, the three even numbers must be in some order along a main
> diagonal.

Neat. So combining the two ideas (even diagonal and 9 triples) there
are only nine cases, all but one of which yield quick contradictions.

2 9 7 2 9 7 4 9 5 4 9 5 6 9 3 6 9 3 9 3 6 9 3 6 9 5 4
. 4 . . 6 . . 2 . . 6 . . 2 . . 4 . 5 2 . 7 4 . 7 6 .
. 5 6 . 3 4 . 7 6 . 3 2 . 7 4 . 5 2 4 . 7 2 . 5 2 . 3

Dan

Date Subject Author
3/24/11 Leroy Quet
3/24/11 Leroy Quet
3/24/11 Ilan Mayer
3/24/11 Dan Hoey
3/24/11 Leroy Quet
3/24/11 Dan Hoey
3/25/11 Leroy Quet
3/26/11 Leroy Quet
3/28/11 Leroy Quet
3/28/11 quasi