A146223 Number of n X n binary arrays symmetric under 180 degree rotation with all ones connected only in a 101-111-010 pattern in any orientation.

1, 1, 1, 1, 5, 21, 64, 303, 1134, 7339, 57196, 589857, 6245651, 99774377, 1593180484, 36586038636, 878744243108, 30250721237881

Offset

1,5

Links

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

Example

Maximal 8 X 8 example
.0.0.0.0.0.1.0.1
.0.0.0.0.0.1.1.1
.0.1.0.0.0.0.1.0
.1.1.1.0.0.1.0.1
.1.0.1.0.0.1.1.1
.0.1.0.0.0.0.1.0
.1.1.1.0.0.0.0.0
.1.0.1.0.0.0.0.0

Crossrefs

Sequence in context: A357723 A342379 A146822 * A181093 A055384 A271540

Adjacent sequences: A146220 A146221 A146222 * A146224 A146225 A146226

Keyword

nonn

Author

R. H. Hardin

Status

approved