A185557 1/3 the number of nX7 0..2 arrays with every element equal to exactly one or two of its horizontal and vertical neighbors

21, 13256, 2792166, 684657326, 160107914496, 38323943289566, 9079893278572272, 2159859526859795892

Offset

1,1

Comments

Column 7 of A185559

Links

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

Example

Some solutions for 4X7 with a(1,1)=0
..0..0..0..1..1..2..2....0..0..0..1..1..2..2....0..0..1..1..2..2..1
..0..1..0..1..0..0..0....0..1..0..2..2..0..2....0..1..0..1..2..2..1
..0..1..0..1..0..2..2....0..1..0..2..1..0..2....0..1..0..1..0..0..2
..0..0..0..2..2..1..1....0..0..0..1..1..2..2....0..0..0..1..1..2..2

Crossrefs

Sequence in context: A250065 A180769 A220643 * A276513 A167063 A115485

Adjacent sequences: A185554 A185555 A185556 * A185558 A185559 A185560

Keyword

nonn

Author

R. H. Hardin Jan 31 2011

Status

approved