- #1

Viking1

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Kindly, can anyone solve the following:

How many combinations:

8 colors, which each can be used twice in the following grid

1 3 5 7

2 4 6 8

where a color can only appear like this

1 with 5

3 with 7

2 with 6

4 with 8

So, non-valid combinations would be

1 with 2

1 with 3

2 with 3

2 with 4 etc. etc.

Thanks a lot!