A146630 Number of n X n binary arrays symmetric about both diagonal and antidiagonal with all ones connected only in a 1010-1111-0010 pattern in any orientation.

1, 1, 1, 1, 1, 1, 1, 3, 9, 19, 33, 61, 181, 701, 2981, 12267, 47389, 212787, 1164819, 7692083, 54594417, 416739483, 3346928919

Offset

1,8

Links

Table of n, a(n) for n=1..23.

Example

Maximal 8 X 8 example
.0.0.0.1.0.1.0.0
.0.0.1.1.1.1.0.0
.0.1.0.1.0.0.1.1
.1.1.1.0.0.0.1.0
.0.1.0.0.0.1.1.1
.1.1.0.0.1.0.1.0
.0.0.1.1.1.1.0.0
.0.0.1.0.1.0.0.0

Crossrefs

Sequence in context: A146638 A147135 A146843 * A146710 A146803 A146702

Adjacent sequences: A146627 A146628 A146629 * A146631 A146632 A146633

Keyword

nonn

Author

R. H. Hardin, Nov 04 2008

Status

approved