

A213545


Number of n X n binary matrices with zero diagonal and directed 3loops in at most one direction (3loop: x(i,j)*x(j,k)*x(k,i)=1, and i,j,k all different)


0




OFFSET

1,2


LINKS



EXAMPLE

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


CROSSREFS



KEYWORD

nonn


AUTHOR



STATUS

approved



