A146825 Number of n X n binary arrays symmetric under horizontal and vertical reflection with all ones connected only in a 1000-1111-0100-0100 pattern in any orientation.

1, 1, 1, 1, 1, 1, 1, 1, 9, 9, 33, 33, 81, 81, 501, 501, 9765, 9765, 253829, 253829, 5201161, 5201161

Offset

1,9

Links

Table of n, a(n) for n=1..22.

Example

Maximal 9 X 9 example:
.0.0.1.0.0.0.1.0.0
.0.0.1.0.0.0.1.0.0
.1.1.1.0.0.0.1.1.1
.0.0.1.1.0.1.1.0.0
.0.0.0.0.0.0.0.0.0
.0.0.1.1.0.1.1.0.0
.1.1.1.0.0.0.1.1.1
.0.0.1.0.0.0.1.0.0
.0.0.1.0.0.0.1.0.0

Crossrefs

Sequence in context: A294691 A356839 A147172 * A147029 A146258 A146173

Adjacent sequences: A146822 A146823 A146824 * A146826 A146827 A146828

Keyword

nonn,more

Author

R. H. Hardin, Nov 04 2008

Status

approved