A147189 Number of n X n binary arrays symmetric about both diagonal and antidiagonal with all ones connected only in a 11000-01110-00011 pattern in any orientation.

1, 1, 1, 1, 1, 1, 1, 1, 3, 5, 11, 19, 53, 119, 315, 741, 2791, 8507, 37441, 131241, 690373, 2947311, 17685311, 87080583, 622517947, 3695889011, 31549600531

Offset

1,9

Links

Table of n, a(n) for n=1..27.

Example

Maximal 9 X 9 example
.0.0.0.0.0.0.1.1.0
.0.0.0.0.1.1.1.0.1
.0.0.0.1.1.0.0.1.1
.0.0.1.0.0.0.0.1.0
.0.1.1.0.0.0.1.1.0
.0.1.0.0.0.0.1.0.0
.1.1.0.0.1.1.0.0.0
.1.0.1.1.1.0.0.0.0
.0.1.1.0.0.0.0.0.0

Crossrefs

Sequence in context: A281380 A117272 A243616 * A118744 A092672 A061068

Adjacent sequences: A147186 A147187 A147188 * A147190 A147191 A147192

Keyword

nonn

Author

R. H. Hardin, Nov 04 2008

Status

approved