A146693 Number of n X n binary arrays symmetric about main diagonal with all ones connected only in a 1100-1100-0111 pattern in any orientation.

1, 1, 1, 1, 3, 9, 23, 49, 265, 1763, 11689, 76179, 790941, 10968467, 170749547, 2982674505, 69135368821, 2071835100571, 74394376040387, 3179634632557555

Offset

1,5

Links

Table of n, a(n) for n=1..20.

Example

Maximal 8 X 8 example
.0.0.0.0.1.1.1.0
.0.0.0.1.1.0.0.0
.0.0.0.1.1.0.0.0
.0.1.1.0.0.1.1.0
.1.1.1.0.0.1.1.1
.1.0.0.1.1.0.0.1
.1.0.0.1.1.0.0.1
.0.0.0.0.1.1.1.0

Crossrefs

Sequence in context: A018555 A147271 A230119 * A227259 A064551 A005783

Adjacent sequences: A146690 A146691 A146692 * A146694 A146695 A146696

Keyword

nonn

Author

R. H. Hardin, Nov 04 2008

Status

approved