A146066 Number of n X n binary arrays symmetric about main diagonal with all ones connected only in a 5-point zee 1,1 2,1 2,2 2,3 3,3 in any orientation.

1, 1, 1, 1, 3, 9, 19, 69, 389, 2287, 15081, 141721, 1694175, 23795099, 418616469, 9434924199, 264113682081, 9153093458787, 397472720900369, 21616544571284115, 1466493314737915869, 124160358455186794957

Offset

1,5

Links

Table of n, a(n) for n=1..22.

Example

Maximal 8 X 8 example
.0.0.1.1.0.1.1.0
.0.0.0.1.0.0.1.0
.1.0.0.1.1.0.1.1
.1.1.1.0.0.1.0.0
.0.0.1.0.0.1.1.1
.1.0.0.1.1.0.0.1
.1.1.1.0.1.0.0.0
.0.0.1.0.1.1.0.0

Crossrefs

Sequence in context: A147070 A130586 A147146 * A164283 A375231 A178963

Adjacent sequences: A146063 A146064 A146065 * A146067 A146068 A146069

Keyword

nonn

Author

R. H. Hardin, Oct 26 2008

Status

approved