A146045 Number of n X n binary arrays symmetric under 180 degree rotation with all ones connected only in a 2X4 tee 1,1 1,2 1,3 2,3 1,4 in any orientation.

1, 1, 1, 5, 17, 49, 267, 1635, 15439, 178481, 2706563, 52897007, 1344799359, 42695435337, 1933850526571, 106233098774339

Offset

1,4

Links

Table of n, a(n) for n=1..16.

Example

Maximal 8 X 8 example
.0.0.0.0.1.1.1.1
.0.1.0.0.0.1.0.0
.1.1.1.1.0.0.1.0
.0.0.0.0.1.1.1.1
.1.1.1.1.0.0.0.0
.0.1.0.0.1.1.1.1
.0.0.1.0.0.0.1.0
.1.1.1.1.0.0.0.0

Crossrefs

Sequence in context: A000337 A147260 A273688 * A086866 A054452 A196310

Adjacent sequences: A146042 A146043 A146044 * A146046 A146047 A146048

Keyword

nonn

Author

R. H. Hardin, Oct 26 2008

Status

approved