A147213 Number of n X n binary arrays symmetric about both diagonal and antidiagonal with all ones connected only in a 1100-0111-0011 pattern in any orientation.

1, 1, 1, 1, 1, 1, 1, 3, 9, 19, 39, 117, 361, 955, 3303, 16663, 85069, 434621, 2513479, 17082851, 120871405, 925679621

Offset

1,8

Links

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

Example

Maximal 8 X 8 example
.0.0.0.0.0.1.1.0
.0.0.0.1.1.1.0.1
.0.0.0.1.1.0.1.1
.0.1.1.0.0.1.1.0
.0.1.1.0.0.1.1.0
.1.1.0.1.1.0.0.0
.1.0.1.1.1.0.0.0
.0.1.1.0.0.0.0.0

Crossrefs

Sequence in context: A038163 A327381 A146819 * A146441 A147341 A208972

Adjacent sequences: A147210 A147211 A147212 * A147214 A147215 A147216

Keyword

nonn

Author

R. H. Hardin, Nov 04 2008

Status

approved