A146662 Number of n X n binary arrays symmetric about both diagonal and antidiagonal with all ones connected only in a 1100-0111-0001 pattern in any orientation.

1, 1, 1, 1, 1, 1, 1, 3, 9, 19, 41, 133, 407, 1175, 4535, 22999, 120797, 662265, 4237243, 30856447, 236921167, 2042840001, 20458483743, 233380921399

Offset

1,8

Links

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

Example

Maximal 8 X 8 example
.0.0.0.0.0.1.1.0
.0.0.0.1.1.1.0.1
.0.0.0.1.0.0.1.1
.0.1.1.0.0.0.1.0
.0.1.0.0.0.1.1.0
.1.1.0.0.1.0.0.0
.1.0.1.1.1.0.0.0
.0.1.1.0.0.0.0.0

Crossrefs

Sequence in context: A241626 A160704 A279673 * A145947 A373309 A153084

Adjacent sequences: A146659 A146660 A146661 * A146663 A146664 A146665

Keyword

nonn

Author

R. H. Hardin, Nov 04 2008

Status

approved