Originally posted by sintubin
since you didn't specify how the half chessboardlooks like, the answer will vary between 0 and the number that I will not quote here but that you obtain by cutting the chessboard with one horizontal or vertical line through the middle.
true, you could cut it accross the diagonal... but that'd just be silly
the sequance 312132 used each of the numbers twice, and each number has that number of other numbers separating them. eg. the 1's have one number between them, the 3's have three numbers between them.
Do the same for numbers 1,2,3 & 4.
Is it possible for 1-5?