A147466 Number of n X n binary arrays symmetric under 180 degree rotation with all ones connected only in a 1100-1111-0011 pattern in any orientation.

1, 1, 1, 1, 1, 9, 21, 63, 297, 1127, 5413, 31109, 218667, 1954511, 18966855, 237663851, 3316716099, 56055493989

Offset

1,6

Links

Table of n, a(n) for n=1..18.

Example

Maximal 8 X 8 example
.0.1.1.0.0.1.1.0
.0.1.1.0.0.1.1.0
.1.1.0.0.1.1.0.0
.1.1.0.0.1.1.0.0
.0.0.1.1.0.0.1.1
.0.0.1.1.0.0.1.1
.0.1.1.0.0.1.1.0
.0.1.1.0.0.1.1.0

Crossrefs

Sequence in context: A020290 A020288 A338007 * A262055 A193276 A173084

Adjacent sequences: A147463 A147464 A147465 * A147467 A147468 A147469

Keyword

nonn

Author

R. H. Hardin

Status

approved