A146660 Number of n X n binary arrays symmetric under horizontal and vertical reflection with all ones connected only in a 1100-0111-0001 pattern in any orientation.

1, 1, 1, 1, 1, 1, 1, 1, 17, 17, 73, 73, 521, 521, 7411, 7411, 207693, 207693, 7583663, 7583663, 399906057, 399906057

Offset

1,9

Links

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

Example

Maximal 9 X 9 example
.0.0.0.0.0.0.0.0.0
.1.0.0.0.0.0.0.0.1
.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
.1.0.0.0.0.0.0.0.1
.0.0.0.0.0.0.0.0.0

Crossrefs

Sequence in context: A146809 A147233 A146817 * A070852 A146596 A146391

Adjacent sequences: A146657 A146658 A146659 * A146661 A146662 A146663

Keyword

nonn

Author

R. H. Hardin, Nov 04 2008

Status

approved