A146250 Number of n X n binary arrays symmetric under horizontal and vertical reflection with all ones connected only in a 110-111-011 pattern in any orientation.

1, 1, 1, 1, 1, 1, 3, 3, 9, 9, 21, 21, 85, 85, 755, 755, 7735, 7735, 87315, 87315, 1464567, 1464567, 39342833, 39342833, 1394115639, 1394115639, 64760833633, 64760833633, 4237428548705, 4237428548705

Offset

1,7

Links

Table of n, a(n) for n=1..30.

Example

Maximal 8 X 8 example
.0.1.1.0.0.1.1.0
.1.1.1.0.0.1.1.1
.1.1.0.0.0.0.1.1
.0.0.0.0.0.0.0.0
.0.0.0.0.0.0.0.0
.1.1.0.0.0.0.1.1
.1.1.1.0.0.1.1.1
.0.1.1.0.0.1.1.0

Crossrefs

Sequence in context: A147072 A146068 A146911 * A232023 A146695 A146442

Adjacent sequences: A146247 A146248 A146249 * A146251 A146252 A146253

Keyword

nonn

Author

R. H. Hardin

Status

approved