A146151 Number of n X n binary arrays symmetric under 180 degree rotation with all ones connected only in an em 1,1 1,2 2,2 2,3 3,3 in any orientation.

1, 1, 1, 3, 9, 27, 119, 633, 3943, 30791, 332473, 4676705, 79725173, 1817184081, 50545874411, 1811092006865

Offset

1,4

Links

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

Example

Maximal 8 X 8 example
.0.1.1.0.0.1.1.0
.1.1.0.0.0.0.1.1
.1.0.0.1.0.0.0.1
.0.0.1.1.0.1.1.0
.0.1.1.0.1.1.0.0
.1.0.0.0.1.0.0.1
.1.1.0.0.0.0.1.1
.0.1.1.0.0.1.1.0

Crossrefs

Sequence in context: A230951 A121746 A323927 * A306681 A254334 A375093

Adjacent sequences: A146148 A146149 A146150 * A146152 A146153 A146154

Keyword

nonn

Author

R. H. Hardin, Oct 27 2008

Status

approved