A146380 Number of n X n binary arrays symmetric under 180 degree rotation with all ones connected only in a 0100-1111-0100 pattern in any orientation.

1, 1, 1, 1, 1, 13, 27, 135, 527, 2581, 17899, 176183, 1596080, 23232289, 321756402, 6986541337, 150961652645, 4812704574943, 154830665386988

Offset

1,6

Links

Table of n, a(n) for n=1..19.

Example

Maximal 8 X 8 example
.0.0.0.0.0.1.0.0
.0.0.0.0.1.1.1.1
.0.1.0.0.0.1.0.0
.1.1.1.1.0.0.1.0
.0.1.0.0.1.1.1.1
.0.0.1.0.0.0.1.0
.1.1.1.1.0.0.0.0
.0.0.1.0.0.0.0.0

Crossrefs

Sequence in context: A098266 A041332 A041334 * A146372 A018946 A042397

Adjacent sequences: A146377 A146378 A146379 * A146381 A146382 A146383

Keyword

nonn

Author

R. H. Hardin

Status

approved