A145757 Number of n X n binary arrays with all ones connected only either three adjacent vertically or three adjacent horizontally.

1, 1, 9, 45, 476, 6933, 199238, 8764691, 657200985, 80295518797, 16444907566268, 5549422397331424, 3112070848837147326

Offset

1,3

Links

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

Example

Maximal 8 X 8 example
.0.1.1.1.0.1.1.1
.0.0.0.0.0.0.0.0
.1.1.1.0.1.1.1.0
.0.0.0.0.0.0.0.1
.1.1.1.0.0.1.0.1
.0.0.0.0.0.1.0.1
.0.0.0.0.0.1.0.0
.0.0.1.1.1.0.0.0

Crossrefs

Sequence in context: A392861 A230063 A009432 * A058824 A244302 A177742

Adjacent sequences: A145754 A145755 A145756 * A145758 A145759 A145760

Keyword

nonn,more

Author

R. H. Hardin, Oct 17 2008

Status

approved