A213955 Number of n X n 0..1 matrices with row and column i=1..n having sum <= i.

2, 10, 138, 5314, 575122, 176041978, 153143689594, 380082566144530, 2699632942815871042, 55016905649245690586122, 3223966155402204759824471786

Offset: 1

Author

R. H. Hardin, Jun 28 2012

Keywords

• nonn

Examples

			Some solutions for n=4
..0..1..0..0....1..0..0..0....1..0..0..0....1..0..0..0....1..0..0..0
..0..0..1..1....0..1..1..0....0..1..0..0....0..1..0..0....0..0..0..0
..1..0..0..1....0..1..0..1....0..0..1..1....0..1..1..0....0..1..1..1
..0..1..1..1....0..0..1..0....0..1..0..0....0..0..1..1....0..0..1..1
		

Crossrefs

Column 1 of A213962.