A146252 Number of n X n binary arrays symmetric about both diagonal and antidiagonal with all ones connected only in a 110-111-011 pattern in any orientation.

1, 1, 3, 1, 5, 5, 15, 23, 69, 89, 411, 639, 3479, 7047, 38787, 94093, 630975, 1734343, 14199053, 45390687, 435447535, 1674184531, 18586794693, 84450110411, 1106569877013, 5872912073625, 91248958842685, 569613725750709

Offset

1,3

Links

Table of n, a(n) for n=1..28.

Example

Maximal 8 X 8 example
.0.0.0.0.0.0.1.1
.0.1.1.0.0.1.1.1
.0.1.1.1.0.1.1.0
.0.0.1.1.0.0.0.0
.0.0.0.0.1.1.0.0
.0.1.1.0.1.1.1.0
.1.1.1.0.0.1.1.0
.1.1.0.0.0.0.0.0

Crossrefs

Sequence in context: A205873 A220479 A146913 * A181641 A049266 A089028

Adjacent sequences: A146249 A146250 A146251 * A146253 A146254 A146255

Keyword

nonn

Author

R. H. Hardin

Status

approved