A147237 Number of n X n binary arrays symmetric under 90 degree rotation with all ones connected only in a 1101-0111-0001 pattern in any orientation.

1, 1, 1, 1, 1, 1, 3, 19, 37, 71, 177, 551, 1807, 6509, 26627, 139987, 688205, 4186827, 24218141, 169157335, 1233973193

Offset

1,7

Links

Table of n, a(n) for n=1..21.

Example

Maximal 8 X 8 example
.0.0.0.1.0.1.1.0
.1.0.0.1.1.1.0.0
.1.1.0.1.0.0.0.0
.0.1.0.0.0.1.1.1
.1.1.1.0.0.0.1.0
.0.0.0.0.1.0.1.1
.0.0.1.1.1.0.0.1
.0.1.1.0.1.0.0.0

Crossrefs

Sequence in context: A283714 A187828 A088786 * A117674 A114704 A167053

Adjacent sequences: A147234 A147235 A147236 * A147238 A147239 A147240

Keyword

nonn

Author

R. H. Hardin, Nov 04 2008

Status

approved