A146436 Number of n X n binary arrays symmetric under 180 degree rotation with all ones connected only in a 101-111-101 pattern in any orientation.

1, 1, 3, 1, 3, 9, 23, 73, 239, 601, 4153, 14191, 114759, 580339, 5550888, 46368603, 562683992, 5393792447, 97221007962, 1178726702163, 29671069397702, 489244079163479

Offset

1,3

Links

Table of n, a(n) for n=1..22.

Example

Maximal 8 X 8 example
.1.1.1.0.0.0.0.0
.0.1.0.0.1.0.1.0
.1.1.1.0.1.1.1.0
.0.0.0.0.1.0.1.0
.0.1.0.1.0.0.0.0
.0.1.1.1.0.1.1.1
.0.1.0.1.0.0.1.0
.0.0.0.0.0.1.1.1

Crossrefs

Sequence in context: A088442 A037095 A160654 * A058842 A155734 A128162

Adjacent sequences: A146433 A146434 A146435 * A146437 A146438 A146439

Keyword

nonn

Author

R. H. Hardin

Status

approved