A146854 Number of n X n binary arrays symmetric under 180 degree rotation with all ones connected only in a 1100-1111-0001 pattern in any orientation.

1, 1, 1, 1, 5, 21, 55, 223, 1323, 7243, 56001, 498505, 5857355, 89335203, 1598206021, 35814813801

Offset

1,5

Links

Table of n, a(n) for n=1..16.

Example

Maximal 8 X 8 example
.0.1.1.0.0.1.1.0
.0.0.1.0.0.0.1.0
.0.0.1.1.0.0.1.1
.0.0.1.1.0.0.1.1
.1.1.0.0.1.1.0.0
.1.1.0.0.1.1.0.0
.0.1.0.0.0.1.0.0
.0.1.1.0.0.1.1.0

Crossrefs

Sequence in context: A096942 A365300 A122244 * A299120 A033275 A166464

Adjacent sequences: A146851 A146852 A146853 * A146855 A146856 A146857

Keyword

nonn

Author

R. H. Hardin, Nov 04 2008

Status

approved