A146062 Number of n X n binary arrays symmetric under 180 degree rotation with all 1's connected only in a 2 X 3 U in any orientation.

1, 1, 1, 5, 13, 37, 193, 825, 4833, 42541, 409765, 5652913, 85462407, 1745289105, 41548085965, 1274611587285, 46878706682435, 2328792987017875

Offset

1,4

Links

Table of n, a(n) for n=1..18.

Example

Maximal 8 X 8 example
.1.1.1.0.0.1.1.1
.1.0.1.0.0.1.0.1
.0.0.0.0.0.0.0.0
.1.0.1.0.0.1.1.1
.1.1.1.0.0.1.0.1
.0.0.0.0.0.0.0.0
.1.0.1.0.0.1.0.1
.1.1.1.0.0.1.1.1

Crossrefs

Sequence in context: A146925 A386525 A146452 * A201612 A129924 A360797

Adjacent sequences: A146059 A146060 A146061 * A146063 A146064 A146065

Keyword

nonn

Author

R. H. Hardin, Oct 26 2008

Status

approved