A146011 Number of n X n binary arrays symmetric about the diagonal and under 90 degree rotation with all ones connected only in a 3X3 tee 1,1 1,2 1,3 2,2 3,2 in any orientation.

1, 1, 1, 1, 1, 1, 2, 1, 4, 1, 9, 3, 31, 9, 123, 22, 539, 75, 3348, 380, 26210, 2417, 248376, 17011, 2847301, 150387, 41349456, 1725197, 766696111, 24767029

Offset

1,7

Links

Table of n, a(n) for n=1..30.

Example

Maximal 9 X 9 example
.0.0.0.0.0.0.0.0.0
.0.0.0.1.1.1.0.0.0
.0.0.0.0.1.0.0.0.0
.0.1.0.0.1.0.0.1.0
.0.1.1.1.0.1.1.1.0
.0.1.0.0.1.0.0.1.0
.0.0.0.0.1.0.0.0.0
.0.0.0.1.1.1.0.0.0
.0.0.0.0.0.0.0.0.0

Crossrefs

Sequence in context: A038001 A147080 A146418 * A104620 A243913 A186724

Adjacent sequences: A146008 A146009 A146010 * A146012 A146013 A146014

Keyword

nonn

Author

R. H. Hardin, Oct 26 2008

Status

approved