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

1,1

Links

Table of n, a(n) for n=1..11.

Example

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.

Sequence in context: A087417 A270589 A171214 * A091990 A014228 A059475

Adjacent sequences: A213952 A213953 A213954 * A213956 A213957 A213958

Keyword

nonn

Author

R. H. Hardin, Jun 28 2012

Status

approved