A147174 Number of n X n binary arrays symmetric about both diagonal and antidiagonal with all ones connected only in a 1000-1111-0010-0010 pattern in any orientation.

1, 1, 1, 1, 1, 1, 1, 1, 3, 9, 19, 35, 81, 217, 621, 1903, 7803, 32967, 151167, 704477, 3742519, 21530169

Offset

1,9

Links

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

Example

Maximal 9 X 9 example
.0.0.0.0.0.0.1.0.0
.0.0.0.1.1.1.1.0.0
.0.0.0.0.1.0.0.1.1
.0.1.0.0.1.0.0.1.0
.0.1.1.1.0.1.1.1.0
.0.1.0.0.1.0.0.1.0
.1.1.0.0.1.0.0.0.0
.0.0.1.1.1.1.0.0.0
.0.0.1.0.0.0.0.0.0

Crossrefs

Sequence in context: A348308 A062748 A325666 * A147158 A014540 A293058

Adjacent sequences: A147171 A147172 A147173 * A147175 A147176 A147177

Keyword

nonn

Author

R. H. Hardin, Nov 04 2008

Status

approved