A146056 Number of n X n binary arrays symmetric under horizontal and vertical reflection with all ones connected only in a 2X3 U in any orientation.

1, 1, 1, 1, 5, 1, 21, 9, 145, 29, 1925, 153, 28297, 2069, 734141, 42313, 33360929, 973281, 2205341673, 38746505, 212529048997, 2736250609, 33748456381053, 283141781389, 8526059147670681, 43072398238613, 3258206098233834291

Offset

1,5

Links

Table of n, a(n) for n=1..27.

Example

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

Crossrefs

Sequence in context: A278544 A095368 A029757 * A101625 A051929 A347487

Adjacent sequences: A146053 A146054 A146055 * A146057 A146058 A146059

Keyword

nonn

Author

R. H. Hardin, Oct 26 2008

Status

approved