A146623 Number of n X n binary arrays symmetric about the diagonal and under 90 degree rotation with all ones connected only in a 1001-1111 pattern in any orientation.

1, 1, 1, 1, 1, 1, 1, 3, 1, 5, 1, 7, 5, 21, 13, 69, 33, 309, 131, 1529, 465, 8153, 2505, 52849, 18109, 418127, 137539, 4312045, 1253575, 52848473

Offset

1,8

Links

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

Example

Maximal 8 X 8 example
.0.0.1.0.0.1.0.0
.0.0.1.1.1.1.0.0
.1.1.0.0.0.0.1.1
.0.1.0.0.0.0.1.0
.0.1.0.0.0.0.1.0
.1.1.0.0.0.0.1.1
.0.0.1.1.1.1.0.0
.0.0.1.0.0.1.0.0

Crossrefs

Sequence in context: A254938 A244149 A147410 * A197943 A318828 A318827

Adjacent sequences: A146620 A146621 A146622 * A146624 A146625 A146626

Keyword

nonn

Author

R. H. Hardin, Nov 04 2008

Status

approved