Number of nX2 arrays containing 2 copies of 0..n-1 with column sums equal.
A268470
Number of nX2 arrays containing 2 copies of 0..n-1 with column sums equal.
Terms
- a(0) =1a(1) =4a(2) =36a(3) =648a(4) =19800a(5) =972000a(6) =69060600a(7) =6756825600a(8) =866219961600
External references
- oeis: A268470