A181234 Number of (2*n)Xn binary matrices with all row sums equal and all column sums equal.

2, 8, 182, 49772, 113400002, 4027811102702, 1237505791330809002

Offset: 1

Author

R. H. Hardin Oct 10 2010

Keywords

• nonn

Comments

Column 2 of A181236

Examples

			Some solutions for 6X3
..1..0..0....0..1..1....1..0..0....1..1..0....0..1..0....1..0..0....0..0..1
..0..1..0....1..0..1....0..1..0....1..1..0....1..0..0....0..0..1....1..0..0
..1..0..0....1..1..0....0..0..1....0..1..1....0..0..1....0..1..0....0..1..0
..0..0..1....1..1..0....0..0..1....0..1..1....0..1..0....0..1..0....1..0..0
..0..0..1....0..1..1....1..0..0....1..0..1....0..0..1....0..0..1....0..1..0
..0..1..0....1..0..1....0..1..0....1..0..1....1..0..0....1..0..0....0..0..1