A146267 Number of n X n binary arrays symmetric about main diagonal with all ones connected only in a 110-111-110 pattern in any orientation.

1, 1, 1, 1, 3, 9, 20, 59, 238, 1339, 8950, 63227, 541368, 5931901, 82015459, 1400527040, 28248253548, 677346206953, 19987158806408, 732068950428064, 33003291678037712, 1801673455589720405, 118568477345258796542

Offset

1,5

Links

Table of n, a(n) for n=1..23.

Example

Maximal 8 X 8 example
.0.0.0.1.1.0.0.0
.0.0.1.1.1.0.0.0
.0.1.0.1.1.0.0.0
.1.1.1.0.0.0.1.1
.1.1.1.0.0.1.1.1
.0.0.0.0.1.0.1.1
.0.0.0.1.1.1.0.0
.0.0.0.1.1.1.0.0

Crossrefs

Sequence in context: A147416 A078841 A147387 * A151420 A196294 A196212

Adjacent sequences: A146264 A146265 A146266 * A146268 A146269 A146270

Keyword

nonn

Author

R. H. Hardin

Status

approved