A146649 Number of n X n binary arrays symmetric under 180 degree rotation with all ones connected only in a 1010-1111-1000 pattern in any orientation.

1, 1, 1, 1, 5, 25, 55, 257, 1343, 7017, 52361, 533979, 5651335, 90178433, 1487870527, 34319557235, 869941319597

Offset

1,5

Links

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

Example

Maximal 8 X 8 example
.0.1.1.1.0.1.1.1
.0.0.1.0.0.0.1.0
.0.0.1.1.0.0.1.1
.0.0.1.0.0.0.1.0
.0.1.0.0.0.1.0.0
.1.1.0.0.1.1.0.0
.0.1.0.0.0.1.0.0
.1.1.1.0.1.1.1.0

Crossrefs

Sequence in context: A044082 A161143 A045576 * A326314 A273357 A146412

Adjacent sequences: A146646 A146647 A146648 * A146650 A146651 A146652

Keyword

nonn

Author

R. H. Hardin, Nov 04 2008

Status

approved