A146932 Number of n X n binary arrays symmetric under 180 degree rotation with all ones connected only in a 1001-1111-1001 pattern in any orientation.

1, 1, 1, 1, 1, 5, 9, 21, 65, 198, 664, 2279, 9527, 44776, 245082, 1574117, 10939250, 91288331, 843940046

Offset

1,6

Links

Table of n, a(n) for n=1..19.

Example

Maximal 8 X 8 example
.1.1.1.0.1.0.0.1
.0.1.0.0.1.1.1.1
.0.1.0.0.1.0.0.1
.1.1.1.0.0.0.0.0
.0.0.0.0.0.1.1.1
.1.0.0.1.0.0.1.0
.1.1.1.1.0.0.1.0
.1.0.0.1.0.1.1.1

Crossrefs

Sequence in context: A097074 A050559 A082676 * A146476 A110200 A063404

Adjacent sequences: A146929 A146930 A146931 * A146933 A146934 A146935

Keyword

nonn

Author

R. H. Hardin, Nov 04 2008

Status

approved