A146259 Number of n X n binary arrays symmetric about main diagonal with all ones connected only in a 110-111-101 pattern in any orientation.

1, 1, 1, 1, 3, 13, 31, 77, 447, 3609, 25623, 200309, 2271887, 36004709, 643384137, 13404301669, 367224822485, 12922817223889, 545705442791831, 28082761867376669, 1838300090661189305

Offset

1,5

Links

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

Example

Maximal 8 X 8 example
.0.0.1.1.1.0.0.0
.0.0.1.1.0.0.0.0
.1.1.0.1.1.0.0.0
.1.1.1.0.0.1.0.1
.1.0.1.0.0.1.1.1
.0.0.0.1.1.0.1.1
.0.0.0.0.1.1.0.0
.0.0.0.1.1.1.0.0

Crossrefs

Sequence in context: A164569 A007686 A147030 * A146174 A147134 A146842

Adjacent sequences: A146256 A146257 A146258 * A146260 A146261 A146262

Keyword

nonn

Author

R. H. Hardin

Status

approved