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

1,1

Comments

Column 2 of A181236

Links

Table of n, a(n) for n=1..7.

Example

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

Crossrefs

Sequence in context: A213200 A317794 A009377 * A156526 A009505 A305737

Adjacent sequences: A181231 A181232 A181233 * A181235 A181236 A181237

Keyword

nonn

Author

R. H. Hardin Oct 10 2010

Status

approved