Number of 12Xn -1,1 arrays such that the sum over i=1..12,j=1..n of i*x(i,j) is zero, the sum of x(i,j) is zero, and rows are nondecreasing (number of ways to distribute n-across galley oarsmen left-right at 12 fore-aft positions so that there are no turning moments on the ship).

A225352

Number of 12Xn -1,1 arrays such that the sum over i=1..12,j=1..n of i*x(i,j) is zero, the sum of x(i,j) is zero, and rows are nondecreasing (number of ways to distribute n-across galley oarsmen left-right at 12 fore-aft positions so that there are no turning moments on the ship).