A146418 Number of n X n binary arrays symmetric about the diagonal and under 90 degree rotation with all ones connected only in a 1000-1111-1000 pattern in any orientation.

1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 4, 1, 9, 3, 31, 9, 107, 21, 365, 62, 1813, 243, 11236, 1174, 84454, 7129, 738542, 48787, 7473236, 396149

Offset

1,9

Links

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

Example

Maximal 9 X 9 example
.0.0.0.1.1.1.0.0.0
.0.0.0.0.1.0.0.0.0
.0.0.0.0.1.0.0.0.0
.1.0.0.0.1.0.0.0.1
.1.1.1.1.0.1.1.1.1
.1.0.0.0.1.0.0.0.1
.0.0.0.0.1.0.0.0.0
.0.0.0.0.1.0.0.0.0
.0.0.0.1.1.1.0.0.0

Crossrefs

Sequence in context: A264148 A038001 A147080 * A146011 A104620 A243913

Adjacent sequences: A146415 A146416 A146417 * A146419 A146420 A146421

Keyword

nonn

Author

R. H. Hardin

Status

approved