A146133 Number of n X n binary arrays symmetric under 90 degree rotation with all ones connected only in a 3X2 zee 1,1 1,2 1,3 2,3 2,4 in any orientation.

1, 1, 1, 1, 1, 3, 17, 33, 85, 255, 1137, 4265, 27311, 122911, 972783, 6003645, 62308027, 499428829, 6712583897, 70003989585, 1225387976695, 16725199996985

Offset

1,6

Links

Table of n, a(n) for n=1..22.

Example

Maximal 8 X 8 example
.0.0.0.0.1.0.0.0
.0.0.0.0.1.1.0.0
.0.1.1.1.0.1.0.0
.1.1.0.0.0.1.0.0
.0.0.1.0.0.0.1.1
.0.0.1.0.1.1.1.0
.0.0.1.1.0.0.0.0
.0.0.0.1.0.0.0.0

Crossrefs

Sequence in context: A309744 A115355 A146021 * A297735 A266062 A031290

Adjacent sequences: A146130 A146131 A146132 * A146134 A146135 A146136

Keyword

nonn

Author

R. H. Hardin, Oct 27 2008

Status

approved