A146279 Number of n X n binary arrays symmetric under 180 degree rotation with all ones connected only in a 110-111-111 pattern in any orientation.

1, 1, 1, 1, 3, 13, 51, 211, 749, 2651, 19761, 133713, 1247055, 13243557, 208954265, 3004516121, 57775455787, 1089272926485, 30671906403639, 864548428805023

Offset

1,5

Links

Table of n, a(n) for n=1..20.

Example

Maximal 8 X 8 example
.0.0.0.0.1.1.1.0
.0.0.0.0.1.1.1.0
.1.1.1.0.1.1.0.0
.1.1.1.0.0.0.1.1
.1.1.0.0.0.1.1.1
.0.0.1.1.0.1.1.1
.0.1.1.1.0.0.0.0
.0.1.1.1.0.0.0.0

Crossrefs

Sequence in context: A360874 A270913 A323266 * A098619 A086608 A291182

Adjacent sequences: A146276 A146277 A146278 * A146280 A146281 A146282

Keyword

nonn

Author

R. H. Hardin

Status

approved