A146138 Number of n X n binary arrays symmetric under horizontal and vertical reflection with all ones connected only in a 5-point barb 1,1 1,2 2,2 2,3 3,2 in any orientation.

1, 1, 1, 1, 1, 1, 9, 9, 33, 33, 153, 153, 3123, 3123, 118071, 118071, 4682615, 4682615, 398324801, 398324801, 67438703311, 67438703311, 18607359075661, 18607359075661, 8942742118054707

Offset

1,7

Links

Table of n, a(n) for n=1..25.

Example

Maximal 8 X 8 example
.0.1.0.0.0.0.1.0
.0.1.1.0.0.1.1.0
.1.1.0.0.0.0.1.1
.0.0.0.0.0.0.0.0
.0.0.0.0.0.0.0.0
.1.1.0.0.0.0.1.1
.0.1.1.0.0.1.1.0
.0.1.0.0.0.0.1.0

Crossrefs

Sequence in context: A146182 A147149 A147277 * A147446 A146447 A145954

Adjacent sequences: A146135 A146136 A146137 * A146139 A146140 A146141

Keyword

nonn

Author

R. H. Hardin, Oct 27 2008

Status

approved