A147253 Number of n X n binary arrays symmetric under 90 degree rotation with all ones connected only in a 11100-00100-00111 pattern in any orientation.

1, 1, 1, 1, 1, 1, 1, 1, 11, 17, 41, 57, 231, 453, 1543, 3457, 18427, 50015, 289401, 862907, 5771143, 20904685, 158696163, 662519097

Offset

1,9

Links

Table of n, a(n) for n=1..24.

Example

Maximal 9 X 9 example
.0.0.0.0.0.1.1.1.0
.1.0.0.0.0.1.0.0.0
.1.0.0.1.1.1.0.0.0
.1.1.1.0.0.0.1.0.0
.0.0.1.0.0.0.1.0.0
.0.0.1.0.0.0.1.1.1
.0.0.0.1.1.1.0.0.1
.0.0.0.1.0.0.0.0.1
.0.1.1.1.0.0.0.0.0

Crossrefs

Sequence in context: A181421 A290530 A163387 * A201476 A057473 A267291

Adjacent sequences: A147250 A147251 A147252 * A147254 A147255 A147256

Keyword

nonn

Author

R. H. Hardin, Nov 04 2008

Status

approved