A146677 Number of n X n binary arrays symmetric about main diagonal with all ones connected only in a 1100-0111-1100 pattern in any orientation.

1, 1, 1, 1, 1, 3, 9, 19, 52, 193, 866, 4709, 29160, 204475, 1745781, 17973283, 218163477, 3154013451, 54291505832, 1101846202608, 26444293196609, 754399567634635, 25615826491870630, 1034470468747498026

Offset

1,6

Links

Table of n, a(n) for n=1..24.

Example

Maximal 8 X 8 example
.0.0.0.0.1.1.0.0
.0.0.1.1.1.0.0.0
.0.1.0.0.1.1.0.0
.0.1.0.0.0.0.0.0
.1.1.1.0.0.0.0.0
.1.0.1.0.0.0.0.0
.0.0.0.0.0.0.0.0
.0.0.0.0.0.0.0.0

Crossrefs

Sequence in context: A102001 A146901 A147477 * A077442 A147455 A146429

Adjacent sequences: A146674 A146675 A146676 * A146678 A146679 A146680

Keyword

nonn

Author

R. H. Hardin, Nov 04 2008

Status

approved