A147344 Number of n X n binary arrays symmetric under 90 degree rotation with all ones connected only in a 0100-0100-1111-0010-0010 pattern in any orientation.

1, 1, 1, 1, 1, 1, 1, 1, 3, 15, 29, 45, 73, 153, 491, 1439, 4619, 16351, 52019, 195927, 800019, 3525897, 17183583, 88313479

Offset

1,9

Links

Table of n, a(n) for n=1..24.

Example

Maximal 9 X 9 example
.0.0.1.0.0.0.1.0.0
.0.0.1.0.1.1.1.0.0
.1.1.1.1.0.0.1.1.1
.0.1.0.0.0.0.1.0.0
.0.1.0.0.0.0.0.1.0
.0.0.1.0.0.0.0.1.0
.1.1.1.0.0.1.1.1.1
.0.0.1.1.1.0.1.0.0
.0.0.1.0.0.0.1.0.0

Crossrefs

Sequence in context: A242571 A067144 A018784 * A201434 A308385 A202506

Adjacent sequences: A147341 A147342 A147343 * A147345 A147346 A147347

Keyword

nonn

Author

R. H. Hardin

Status

approved