A147441 Number of n X n binary arrays symmetric about the diagonal and under 90 degree rotation with all ones connected only in a 1010-1111-1010 pattern in any orientation.

1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 4, 1, 8, 3, 24, 9

Offset

1,9

Links

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

Example

Maximal 9 X 9 example
.0.0.0.1.1.1.0.0.0
.0.0.0.0.1.0.0.0.0
.0.0.0.1.1.1.0.0.0
.1.0.1.0.1.0.1.0.1
.1.1.1.1.0.1.1.1.1
.1.0.1.0.1.0.1.0.1
.0.0.0.1.1.1.0.0.0
.0.0.0.0.1.0.0.0.0
.0.0.0.1.1.1.0.0.0

Crossrefs

Sequence in context: A366842 A115120 A147373 * A146269 A146679 A146221

Adjacent sequences: A147438 A147439 A147440 * A147442 A147443 A147444

Keyword

nonn

Author

R. H. Hardin

Status

approved