A146004 Number of n X n binary arrays symmetric under 180 degree rotation with all ones connected only in a 3X3 plus 2,1 2,2 2,3 1,2 3,2.

1, 1, 2, 1, 4, 7, 21, 46, 195, 635, 3736, 16722, 140702, 874897, 10218521, 89150959, 1456627028, 17686096248, 403908679949, 6882785245717, 219237062845023, 5210440958351021, 232082441606979544, 7714095184686817142

Offset

1,3

Links

Table of n, a(n) for n=1..24.

Example

Maximal 8 X 8 example
.0.0.0.0.0.0.1.0
.0.0.0.0.0.1.1.1
.0.0.1.0.0.0.1.0
.0.1.1.1.0.1.0.0
.0.0.1.0.1.1.1.0
.0.1.0.0.0.1.0.0
.1.1.1.0.0.0.0.0
.0.1.0.0.0.0.0.0

Crossrefs

Sequence in context: A184345 A045625 A294501 * A001933 A038557 A348678

Adjacent sequences: A146001 A146002 A146003 * A146005 A146006 A146007

Keyword

nonn

Author

R. H. Hardin, Oct 26 2008

Status

approved