A146228 Number of n X n binary arrays symmetric about both diagonal and antidiagonal with all ones connected only in a 1100-1111 pattern in any orientation.

1, 1, 1, 1, 1, 1, 3, 7, 15, 27, 53, 167, 715, 3083, 12351, 50227, 261707, 1665665, 12424027, 97246107, 810664323, 7548517875, 83664650731, 1054301327283

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
.0.0.1.1.1.1.0.0
.0.1.0.0.0.0.1.1
.0.1.0.0.0.0.1.1
.1.1.0.0.0.0.1.0
.1.1.0.0.0.0.1.0
.0.0.1.1.1.1.0.0
.0.0.1.1.0.0.0.0

Crossrefs

Sequence in context: A378278 A147127 A146726 * A139806 A143701 A147638

Adjacent sequences: A146225 A146226 A146227 * A146229 A146230 A146231

Keyword

nonn

Author

R. H. Hardin

Status

approved