A181238 Number of (4*n)X4 binary matrices with all row sums equal and all column sums equal.

140, 49772, 33235358, 27896484332, 26012734507190, 25785064658274014, 26631749414632177802, 28342597507242978860012, 30862541359435652055581702, 34221243248277031078812700022, 38507504930060734566868274154362

Offset: 1

Author

R. H. Hardin Oct 10 2010

Keywords

• nonn

Comments

Row 4 of A181236

Examples

			Some solutions for 4X4
..1..1..0..1....1..1..0..0....0..1..0..1....0..1..0..0....1..0..0..1
..1..0..1..1....0..0..1..1....1..0..0..1....0..0..0..1....1..1..0..0
..0..1..1..1....1..0..0..1....0..1..1..0....0..0..1..0....0..0..1..1
..1..1..1..0....0..1..1..0....1..0..1..0....1..0..0..0....0..1..1..0
		

Links

• R. H. Hardin, Table of n, a(n) for n=1..22