A145971 Number of n X n binary arrays symmetric under 180 degree rotation with all ones connected only in a one by five or five by one block.

1, 1, 1, 1, 9, 9, 54, 93, 747, 1903, 18738, 80363, 1083847, 6706491, 120203159, 1028058854

Offset

1,5

Links

Table of n, a(n) for n=1..16.

Example

Maximal 8 X 8 example
.1.1.1.1.1.0.0.1
.0.0.0.0.0.0.0.1
.0.1.1.1.1.1.0.1
.1.0.0.0.0.0.0.1
.1.0.0.0.0.0.0.1
.1.0.1.1.1.1.1.0
.1.0.0.0.0.0.0.0
.1.0.0.1.1.1.1.1

Crossrefs

Sequence in context: A014718 A371374 A339324 * A241868 A243125 A270008

Adjacent sequences: A145968 A145969 A145970 * A145972 A145973 A145974

Keyword

nonn

Author

R. H. Hardin, Oct 25 2008

Status

approved