A146830 Number of n X n binary arrays symmetric under 180 degree rotation with all ones connected only in a 1000-1111-0100-0100 pattern in any orientation.

1, 1, 1, 1, 1, 5, 25, 97, 477, 2077, 8985, 74677, 698825, 7828097, 101646585, 1842811427

Offset

1,6

Links

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

Example

Maximal 8 X 8 example
.0.1.0.0.0.1.0.0
.0.1.0.0.0.1.0.0
.1.1.1.1.0.1.1.1
.1.0.0.0.1.1.0.0
.0.0.1.1.0.0.0.1
.1.1.1.0.1.1.1.1
.0.0.1.0.0.0.1.0
.0.0.1.0.0.0.1.0

Crossrefs

Sequence in context: A197085 A273747 A201841 * A316778 A255612 A022729

Adjacent sequences: A146827 A146828 A146829 * A146831 A146832 A146833

Keyword

nonn

Author

R. H. Hardin, Nov 04 2008

Status

approved