A146158 Number of n X n binary arrays symmetric under 90 degree rotation with all ones connected only either as two by three or three by two blocks.

1, 1, 1, 1, 1, 3, 8, 14, 23, 49, 124, 341, 1108, 3645, 13272, 50449, 210792, 970179, 4987095, 27600222, 171681370, 1133281367, 8288847384, 64922838278, 565664086802, 5311135075018, 55657682314667, 624953409635386

Offset

1,6

Links

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

Example

Maximal 8 X 8 example
.0.0.0.1.1.0.0.0
.0.0.0.1.1.0.0.0
.0.0.0.1.1.0.0.0
.1.1.1.0.0.1.1.1
.1.1.1.0.0.1.1.1
.0.0.0.1.1.0.0.0
.0.0.0.1.1.0.0.0
.0.0.0.1.1.0.0.0

Crossrefs

Sequence in context: A014848 A140479 A264689 * A062354 A257644 A135940

Adjacent sequences: A146155 A146156 A146157 * A146159 A146160 A146161

Keyword

nonn

Author

R. H. Hardin, Oct 27 2008

Status

approved