A147472 Number of n X n binary arrays symmetric about the diagonal and under 90 degree rotation with all ones connected only in a 1100-1111-0100-0100 pattern in any orientation.

1, 1, 1, 1, 1, 1, 1, 1, 3, 3, 5, 5, 9, 9, 19, 19, 55, 55, 245, 245, 1021, 1021, 4107, 4107, 20679, 20679

Offset

1,9

Links

Table of n, a(n) for n=1..26.

Example

Maximal 9 X 9 example
.0.0.1.0.0.0.1.0.0
.0.0.1.0.0.0.1.0.0
.1.1.1.1.0.1.1.1.1
.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
.1.1.1.1.0.1.1.1.1
.0.0.1.0.0.0.1.0.0
.0.0.1.0.0.0.1.0.0

Crossrefs

Sequence in context: A062130 A151970 A049644 * A146914 A146253 A147040

Adjacent sequences: A147469 A147470 A147471 * A147473 A147474 A147475

Keyword

nonn

Author

R. H. Hardin

Status

approved