A213608 Number of n X n binary matrices with zero diagonal and x(i,j)+x(j,k)+x(k,i) not equal to one for i,j,k all different

1, 4, 25, 175, 1572, 19285, 321925, 7695406, 271013005

Offset

1,2

Links

Table of n, a(n) for n=1..9.

Example

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

Crossrefs

Sequence in context: A084210 A093683 A006348 * A369325 A324169 A213231

Adjacent sequences: A213605 A213606 A213607 * A213609 A213610 A213611

Keyword

nonn

Author

R. H. Hardin Jun 16 2012

Status

approved