A146287 Number of n X n binary arrays symmetric under 180 degree rotation with all ones connected only in a 111-110-111 pattern in any orientation.

1, 1, 1, 1, 1, 13, 49, 205, 661, 1997, 13307, 88591, 614455, 6581035, 95397503, 1522572859, 23440615715, 367710019427, 8011532526037, 207007785752989, 6626542824985383

Offset

1,6

Links

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

Example

Maximal 8 X 8 example
.0.0.0.0.0.1.1.1
.1.1.1.0.0.0.1.1
.1.1.0.0.0.1.1.1
.1.1.1.0.0.0.0.0
.0.0.0.0.0.1.1.1
.1.1.1.0.0.0.1.1
.1.1.0.0.0.1.1.1
.1.1.1.0.0.0.0.0

Crossrefs

Sequence in context: A274974 A251142 A319086 * A289999 A147346 A147452

Adjacent sequences: A146284 A146285 A146286 * A146288 A146289 A146290

Keyword

nonn

Author

R. H. Hardin

Status

approved