A146059 Number of n X n binary arrays symmetric about the diagonal and under 90 degree rotation with all ones connected only in a 2X3 U in any orientation.

1, 1, 1, 1, 1, 1, 3, 1, 5, 1, 11, 5, 41, 13, 189, 31, 927, 133, 5603, 759, 45359, 5033, 469791, 38887, 5816617, 382421, 90000163, 4832387, 1751237935, 75700651

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
.0.0.0.1.0.1.0.0.0
.0.0.0.1.1.1.0.0.0
.0.1.1.0.0.0.1.1.0
.0.0.1.0.0.0.1.0.0
.0.1.1.0.0.0.1.1.0
.0.0.0.1.1.1.0.0.0
.0.0.0.1.0.1.0.0.0
.0.0.0.0.0.0.0.0.0

Crossrefs

Sequence in context: A330773 A112031 A146285 * A046531 A289310 A160085

Adjacent sequences: A146056 A146057 A146058 * A146060 A146061 A146062

Keyword

nonn

Author

R. H. Hardin, Oct 26 2008

Status

approved