A147177 Number of n X n binary arrays symmetric under 180 degree rotation with all ones connected only in a 1000-1111-0010-0010 pattern in any orientation.

1, 1, 1, 1, 1, 5, 25, 93, 439, 1973, 9767, 71707, 630927, 7316817, 94092203, 1666775933

Offset

1,6

Links

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

Example

Maximal 8 X 8 example
.0.0.1.0.0.0.1.0
.1.1.1.0.1.1.1.0
.0.0.1.0.0.0.1.0
.0.0.1.1.0.0.1.1
.1.1.0.0.1.1.0.0
.0.1.0.0.0.1.0.0
.0.1.1.1.0.1.1.1
.0.1.0.0.0.1.0.0

Crossrefs

Sequence in context: A224148 A265929 A297452 * A057255 A134140 A225011

Adjacent sequences: A147174 A147175 A147176 * A147178 A147179 A147180

Keyword

nonn

Author

R. H. Hardin, Nov 04 2008

Status

approved