A147111 Number of n X n binary arrays symmetric about both diagonal and antidiagonal with all ones connected only in a 1000-1000-1111-0010 pattern in any orientation.

1, 1, 1, 1, 1, 1, 1, 1, 3, 9, 19, 33, 77, 215, 619, 1943, 7543, 33395, 150047, 720261, 3747953, 21922241

Offset

1,9

Links

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

Example

Maximal 9 X 9 example
.0.0.0.0.1.1.1.0.0
.0.0.0.0.1.0.0.0.0
.0.0.0.1.1.0.0.0.1
.0.0.1.0.1.0.0.0.1
.1.1.1.1.0.1.1.1.1
.1.0.0.0.1.0.1.0.0
.1.0.0.0.1.1.0.0.0
.0.0.0.0.1.0.0.0.0
.0.0.1.1.1.0.0.0.0

Crossrefs

Sequence in context: A146614 A146670 A146409 * A146401 A146465 A147119

Adjacent sequences: A147108 A147109 A147110 * A147112 A147113 A147114

Keyword

nonn

Author

R. H. Hardin, Nov 04 2008

Status

approved