A146648 Number of n X n binary arrays symmetric under 90 degree rotation with all ones connected only in a 1010-1111-1000 pattern in any orientation.

1, 1, 1, 1, 1, 1, 7, 13, 45, 61, 187, 447, 2017, 5419, 35435, 111161, 866245, 3379807, 30738337, 147143823, 1633304661

Offset

1,7

Links

Table of n, a(n) for n=1..21.

Example

Maximal 8 X 8 example
.0.0.0.0.1.1.1.0
.1.0.1.0.0.1.0.0
.1.1.1.1.0.1.1.0
.1.0.0.0.0.1.0.0
.0.0.1.0.0.0.0.1
.0.1.1.0.1.1.1.1
.0.0.1.0.0.1.0.1
.0.1.1.1.0.0.0.0

Crossrefs

Sequence in context: A023286 A287685 A159305 * A219501 A267310 A153119

Adjacent sequences: A146645 A146646 A146647 * A146649 A146650 A146651

Keyword

nonn

Author

R. H. Hardin, Nov 04 2008

Status

approved