A146239 Number of n X n binary arrays symmetric under 180 degree rotation with all ones connected only in a 110-111-001 pattern in any orientation.

1, 1, 1, 1, 9, 41, 201, 1157, 6733, 60161, 712733, 11701425, 239309475, 6797981481, 227189935315, 9296498773239, 488912114784905

Offset

1,5

Links

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

Example

Maximal 8 X 8 example
.0.1.1.0.0.1.1.0
.1.1.1.0.0.1.1.1
.1.0.0.0.1.0.0.1
.0.1.1.0.1.1.1.0
.0.1.1.1.0.1.1.0
.1.0.0.1.0.0.0.1
.1.1.1.0.0.1.1.1
.0.1.1.0.0.1.1.0

Crossrefs

Sequence in context: A276780 A183916 A199311 * A083085 A147283 A171422

Adjacent sequences: A146236 A146237 A146238 * A146240 A146241 A146242

Keyword

nonn

Author

R. H. Hardin

Status

approved