A146268 Number of n X n binary arrays symmetric about both diagonal and antidiagonal with all ones connected only in a 110-111-110 pattern in any orientation.

1, 1, 1, 1, 1, 1, 2, 5, 10, 17, 30, 77, 254, 873, 2865, 9282, 36476, 176379, 950600, 5334620, 30998066, 200015663, 1516056134, 12927161092, 120013319909, 1186872290095, 12868902178120, 156796551881590

Offset

1,7

Links

Table of n, a(n) for n=1..28.

Example

Maximal 8 X 8 example
.0.0.0.1.1.1.0.0
.0.0.0.1.1.1.0.0
.0.0.0.0.1.0.1.1
.1.1.0.0.0.1.1.1
.1.1.1.0.0.0.1.1
.1.1.0.1.0.0.0.0
.0.0.1.1.1.0.0.0
.0.0.1.1.1.0.0.0

Crossrefs

Sequence in context: A173060 A173520 A360749 * A038358 A107482 A227363

Adjacent sequences: A146265 A146266 A146267 * A146269 A146270 A146271

Keyword

nonn

Author

R. H. Hardin

Status

approved