A146274 Number of n X n binary arrays symmetric under horizontal and vertical reflection with all ones connected only in a 110-111-111 pattern in any orientation.

1, 1, 1, 1, 1, 1, 5, 5, 17, 17, 39, 39, 173, 173, 3199, 3199, 51175, 51175, 661225, 661225, 13583567, 13583567, 722876085, 722876085, 45766294357, 45766294357, 3140059939559

Offset

1,7

Links

Table of n, a(n) for n=1..27.

Example

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

Crossrefs

Sequence in context: A146647 A146719 A147469 * A147037 A146796 A146836

Adjacent sequences: A146271 A146272 A146273 * A146275 A146276 A146277

Keyword

nonn

Author

R. H. Hardin

Status

approved