A146247 Number of n X n binary arrays symmetric under 180 degree rotation with all ones connected only in a 110-111-010 pattern in any orientation.

1, 1, 1, 1, 7, 21, 73, 363, 1597, 12869, 120523, 1325159, 19641005, 334866625, 7674660113, 211567083435, 7388903356109, 318730605323017, 17659730470419149

Offset

1,5

Links

Table of n, a(n) for n=1..19.

Example

Maximal 8 X 8 example
.0.1.0.0.0.0.1.0
.1.1.1.0.0.1.1.1
.1.1.0.0.0.0.1.1
.0.0.0.0.0.0.0.0
.0.0.0.0.0.0.0.0
.1.1.0.0.0.0.1.1
.1.1.1.0.0.1.1.1
.0.1.0.0.0.0.1.0

Crossrefs

Sequence in context: A208534 A135576 A153497 * A241431 A147003 A110683

Adjacent sequences: A146244 A146245 A146246 * A146248 A146249 A146250

Keyword

nonn

Author

R. H. Hardin

Status

approved