+19 Find the number of ways of arranging the numbers 1, 2, 3, ... 9 in a circle, so that the sum of any three adjacent numbers is divisible by 3. (Two arrangements are considered the same if one arrangement can be rotated to obtain the other.
+37146 Just put them in a circle in order 1 -2 -3-4-5-6-7-8-9 voila! (well....that is ONE way)
and here is another 1-3-5-7-9-2-4-6-8
+37146 ...and you can shift all of these.....take the first three numbers and put them in the middle
456 123 789
792 135 468
729 486 153 Well, I have found 6 so far I do not know how to calculate the number possible though !!
