A213596 Number of n X n binary matrices with zero diagonal and x(i,j), x(j,k) and x(k,i) not all equal for i,j,k all different

1, 4, 36, 450, 5172, 75204, 1353240, 27948312

Offset

1,2

Links

Table of n, a(n) for n=1..8.

Example

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

Crossrefs

Sequence in context: A136224 A321963 A307903 * A009533 A135906 A197446

Adjacent sequences: A213593 A213594 A213595 * A213597 A213598 A213599

Keyword

nonn

Author

R. H. Hardin Jun 15 2012

Status

approved