A146605 Number of n X n binary arrays symmetric about main diagonal with all ones connected only in a 1000-1111-0001 pattern in any orientation.

1, 1, 1, 1, 1, 3, 9, 19, 59, 237, 1193, 6925, 46535, 385115, 3834729, 46129325, 665267927, 11525172145, 240724568637, 6036636466243, 182136263500283, 6609883325424453

Offset

1,6

Links

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

Example

Maximal 8 X 8 example
.0.0.0.1.1.0.0.0
.0.0.0.0.1.0.0.0
.0.0.0.0.1.0.0.0
.1.0.0.0.1.1.0.0
.1.1.1.1.0.0.0.0
.0.0.0.1.0.0.0.0
.0.0.0.0.0.0.0.0
.0.0.0.0.0.0.0.0

Crossrefs

Sequence in context: A146429 A297390 A018316 * A147070 A130586 A147146

Adjacent sequences: A146602 A146603 A146604 * A146606 A146607 A146608

Keyword

nonn

Author

R. H. Hardin, Nov 04 2008

Status

approved