A190657 Half the number of n X n symmetric binary matrices with no element unequal to a strict majority of its diagonal, vertical and horizontal neighbors.

1, 1, 3, 10, 42, 244, 2031, 22714, 342292, 6943430, 188479666, 6843502049, 331910774405, 21483424837024, 1854744805774187, 213498320443922663, 32758157589935274374

Offset

1,3

Links

Table of n, a(n) for n=1..17.

Example

Some solutions for n=5 with a(1,1)=0:
..0..0..1..1..1....0..0..0..0..0....0..0..0..0..0....0..0..0..0..0
..0..0..0..1..1....0..1..1..1..0....0..0..0..1..1....0..1..1..0..0
..1..0..0..0..0....0..1..1..1..1....0..0..1..1..1....0..1..1..1..1
..1..1..0..0..0....0..1..1..1..1....0..1..1..1..1....0..0..1..1..1
..1..1..0..0..0....0..0..1..1..1....0..1..1..1..1....0..0..1..1..1

Crossrefs

Sequence in context: A232606 A334270 A185621 * A143523 A288813 A306237

Adjacent sequences: A190654 A190655 A190656 * A190658 A190659 A190660

Keyword

nonn

Author

R. H. Hardin, May 16 2011

Status

approved