Number of nX3 -1,1 arrays such that the sum over i=1..n,j=1..3 of i*x(i,j) is zero, the sum of x(i,j) is zero, and rows are nondecreasing (number of ways to distribute 3-across galley oarsmen left-right at n fore-aft positions so that there are no turning moments on the ship).
A225339
Number of nX3 -1,1 arrays such that the sum over i=1..n,j=1..3 of i*x(i,j) is zero, the sum of x(i,j) is zero, and rows are nondecreasing (number of ways to distribute 3-across galley oarsmen left-right at n fore-aft positions so that there are no turning moments on the ship).
Terms
- a(0) =0a(1) =0a(2) =0a(3) =6a(4) =0a(5) =0a(6) =0a(7) =410a(8) =0a(9) =0a(10) =0a(11) =47990a(12) =0a(13) =0a(14) =0a(15) =7030132a(16) =0a(17) =0a(18) =0a(19) =1163743294a(20) =0a(21) =0a(22) =0a(23) =208310242542a(24) =0a(25) =0a(26) =0a(28) =0a(29) =0a(30) =0
External references
- oeis: A225339