A146724 Number of n X n binary arrays symmetric under horizontal and vertical reflection with all ones connected only in a 1101-0111 pattern in any orientation.

1, 1, 1, 1, 1, 1, 1, 1, 25, 25, 197, 197, 1531, 1531, 31791, 31791, 876801, 876801, 39890653, 39890653, 2918403939, 2918403939

Offset

1,9

Links

Table of n, a(n) for n=1..22.

Example

Maximal 9 X 9 example
.0.0.0.0.0.0.0.0.0
.0.0.0.0.0.0.0.0.0
.1.0.1.1.0.1.1.0.1
.1.1.1.0.0.0.1.1.1
.0.0.0.0.0.0.0.0.0
.1.1.1.0.0.0.1.1.1
.1.0.1.1.0.1.1.0.1
.0.0.0.0.0.0.0.0.0
.0.0.0.0.0.0.0.0.0

Crossrefs

Sequence in context: A147507 A146865 A146740 * A165846 A135218 A133507

Adjacent sequences: A146721 A146722 A146723 * A146725 A146726 A146727

Keyword

nonn

Author

R. H. Hardin, Nov 04 2008

Status

approved