A146608 Number of n X n binary arrays symmetric under 90 degree rotation with all ones connected only in a 1000-1111-0001 pattern in any orientation.

1, 1, 1, 1, 1, 1, 3, 9, 21, 41, 85, 247, 661, 2133, 7669, 30043, 131633, 623713, 3176911, 18218893, 109622217, 754540743, 5491953507, 45422445535

Offset

1,7

Links

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

Example

Maximal 8 X 8 example
.0.0.0.0.1.1.0.0
.0.0.0.1.0.1.0.0
.1.1.1.1.0.1.0.0
.1.0.0.0.0.1.1.0
.0.1.1.0.0.0.0.1
.0.0.1.0.1.1.1.1
.0.0.1.0.1.0.0.0
.0.0.1.1.0.0.0.0

Crossrefs

Sequence in context: A024173 A097119 A374585 * A161214 A354961 A213396

Adjacent sequences: A146605 A146606 A146607 * A146609 A146610 A146611

Keyword

nonn

Author

R. H. Hardin, Nov 04 2008

Status

approved