A146134 Number of n X n binary arrays symmetric under 180 degree rotation with all ones connected only in a 3X2 zee 1,1 1,2 1,3 2,3 2,4 in any orientation.

1, 1, 1, 5, 17, 39, 241, 1589, 13237, 156057, 2242755, 43222843, 1066074605

Offset

1,4

Links

Table of n, a(n) for n=1..13.

Example

Maximal 8 X 8 example
.0.1.0.0.1.1.1.0
.1.1.0.0.0.0.1.1
.1.0.0.1.1.0.0.0
.1.0.0.0.1.1.1.0
.0.1.1.1.0.0.0.1
.0.0.0.1.1.0.0.1
.1.1.0.0.0.0.1.1
.0.1.1.1.0.0.1.0

Crossrefs

Sequence in context: A147467 A146272 A147035 * A011931 A260981 A078866

Adjacent sequences: A146131 A146132 A146133 * A146135 A146136 A146137

Keyword

nonn

Author

R. H. Hardin, Oct 27 2008

Status

approved