A146153 Number of n X n binary arrays symmetric under horizontal reflection with all ones connected only either as two by three or three by two blocks.

1, 1, 3, 3, 9, 11, 82, 254, 1669, 6665, 68316, 226521, 4561686, 23734103, 704383992, 5907579541, 236178663400, 2337315883467, 150056765859689, 1811327966926780, 189399759509400492, 3276661629995792339, 507766610202105772758

Offset

1,3

Links

Table of n, a(n) for n=1..23.

Example

Maximal 8 X 8 example
.1.1.1.0.0.1.1.1
.1.1.1.0.0.1.1.1
.0.0.0.0.0.0.0.0
.1.1.1.0.0.1.1.1
.1.1.1.0.0.1.1.1
.0.0.0.0.0.0.0.0
.1.1.1.0.0.1.1.1
.1.1.1.0.0.1.1.1

Crossrefs

Sequence in context: A124281 A351869 A320293 * A339028 A173048 A165992

Adjacent sequences: A146150 A146151 A146152 * A146154 A146155 A146156

Keyword

nonn

Author

R. H. Hardin, Oct 27 2008

Status

approved