A190625 Half the number of n X n symmetric binary matrices with no element equal to a strict majority of its horizontal and vertical neighbors

1, 1, 3, 9, 46, 338, 3788, 62929, 1549089, 56951770, 3109920701, 252393913470, 30471276950027, 5468189500564227, 1458879136021929400, 578685384553802577987, 341244992947305097698156

Offset

1,3

Links

R. H. Hardin, Table of n, a(n) for n = 1..18

Example

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

Crossrefs

Sequence in context: A180501 A188678 A107090 * A317079 A190627 A221986

Adjacent sequences: A190622 A190623 A190624 * A190626 A190627 A190628

Keyword

nonn

Author

R. H. Hardin May 14 2011

Status

approved