A190628 Half the number of n X n symmetric binary matrices with no element equal to a strict majority of its diagonal, vertical and horizontal neighbors

1, 1, 5, 37, 401, 7177, 211675, 10163916, 789061887, 99261256018, 20257890922045, 6705845140373654, 3599724849478263520

Offset

1,3

Links

Table of n, a(n) for n=1..13.

Example

Some solutions for n=4 with a(1,1)=0
..0..1..1..1....0..1..1..0....0..1..1..1....0..1..0..0....0..1..0..0
..1..0..0..0....1..0..0..0....1..1..0..0....1..1..0..1....1..0..0..1
..1..0..1..1....1..0..1..1....1..0..1..0....0..0..0..1....0..0..1..1
..1..0..1..0....0..0..1..0....1..0..0..1....0..1..1..0....0..1..1..0

Crossrefs

Sequence in context: A273954 A092649 A179923 * A333285 A209671 A173796

Adjacent sequences: A190625 A190626 A190627 * A190629 A190630 A190631

Keyword

nonn

Author

R. H. Hardin May 14 2011

Status

approved