Number of nX8 -1,1 arrays such that the sum over i=1..n,j=1..8 of i*x(i,j) is zero, the sum of x(i,j) is zero, and rows are nondecreasing (number of ways to distribute 8-across galley oarsmen left-right at n fore-aft positions so that there are no turning moments on the ship).

A225344

Number of nX8 -1,1 arrays such that the sum over i=1..n,j=1..8 of i*x(i,j) is zero, the sum of x(i,j) is zero, and rows are nondecreasing (number of ways to distribute 8-across galley oarsmen left-right at n fore-aft positions so that there are no turning moments on the ship).

Terms

    a(0) =1a(1) =1a(2) =5a(3) =27a(4) =171a(5) =1081a(6) =7261a(7) =50659a(8) =364051a(9) =2676331a(10) =20044255a(11) =152452967a(12) =1174757541a(13) =9154016699a(14) =72023900129a(15) =571498084391

External references