A146717 Number of n X n binary arrays symmetric about main diagonal with all ones connected only in a 1100-1111-1000 pattern in any orientation.

1, 1, 1, 1, 1, 5, 17, 39, 155, 745, 4705, 39573, 369483, 3970963, 54943873, 950039207, 20417177215, 545483266919, 17663079620537, 695250063366563, 33778790635375371

Offset

1,6

Links

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

Example

Maximal 8 X 8 example
.0.0.0.1.1.1.0.0
.0.0.0.1.1.0.1.0
.0.0.0.0.1.0.1.0
.1.1.0.0.1.0.1.1
.1.1.1.1.0.1.1.1
.1.0.0.0.1.0.0.0
.0.1.1.1.1.0.0.0
.0.0.0.1.1.0.0.0

Crossrefs

Sequence in context: A147165 A147257 A146645 * A147467 A146272 A147035

Adjacent sequences: A146714 A146715 A146716 * A146718 A146719 A146720

Keyword

nonn

Author

R. H. Hardin, Nov 04 2008

Status

approved