A146428 Number of n X n binary arrays symmetric under 180 degree rotation with all ones connected only in a 1010-1111 pattern in any orientation.

1, 1, 1, 5, 17, 37, 137, 887, 6015, 58025, 613977, 8063295, 140732661, 3250417071

Offset

1,4

Links

Table of n, a(n) for n=1..14.

Example

Maximal 8 X 8 example
.1.1.0.0.1.0.1.1
.0.1.0.0.1.1.0.1
.1.1.0.0.1.0.1.1
.0.1.0.0.1.1.0.1
.1.0.1.1.0.0.1.0
.1.1.0.1.0.0.1.1
.1.0.1.1.0.0.1.0
.1.1.0.1.0.0.1.1

Crossrefs

Sequence in context: A282511 A147181 A146850 * A146235 A087728 A072332

Adjacent sequences: A146425 A146426 A146427 * A146429 A146430 A146431

Keyword

nonn

Author

R. H. Hardin

Status

approved