Number of 7Xn -1,1 arrays such that the sum over i=1..7,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 7 fore-aft positions so that there are no turning moments on the ship).
A225347
Number of 7Xn -1,1 arrays such that the sum over i=1..7,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 7 fore-aft positions so that there are no turning moments on the ship).
Terms
- a(0) =0a(1) =33a(2) =0a(3) =395a(4) =0a(5) =2073a(6) =0a(7) =7261a(8) =0a(9) =19709a(10) =0a(11) =45385a(12) =0a(13) =92673a(14) =0a(15) =173189a(16) =0a(17) =301799a(18) =0a(19) =497661a(20) =0a(21) =783969a(22) =0a(23) =1189311a(24) =0a(25) =1747059a(26) =0a(27) =2497109a(28) =0a(29) =3484867
External references
- oeis: A225347