A146221 Number of n X n binary arrays symmetric about the diagonal and under 90 degree rotation with all ones connected only in a 101-111-010 pattern in any orientation.

1, 1, 1, 1, 1, 1, 2, 1, 4, 1, 8, 3, 27, 9, 104, 20, 436, 63, 2340, 272, 15459, 1557, 131790, 10412, 1346197, 77761, 16419748, 729051, 247609178, 8641753

Offset

1,7

Links

Table of n, a(n) for n=1..30.

Example

Maximal 9 X 9 example
.0.0.0.0.0.0.0.0.0
.0.0.0.1.0.1.0.0.0
.0.0.0.1.1.1.0.0.0
.0.1.1.0.1.0.1.1.0
.0.0.1.1.0.1.1.0.0
.0.1.1.0.1.0.1.1.0
.0.0.0.1.1.1.0.0.0
.0.0.0.1.0.1.0.0.0
.0.0.0.0.0.0.0.0.0

Crossrefs

Sequence in context: A147441 A146269 A146679 * A147457 A355226 A107061

Adjacent sequences: A146218 A146219 A146220 * A146222 A146223 A146224

Keyword

nonn

Author

R. H. Hardin

Status

approved