A146434 Number of n X n binary arrays symmetric about the diagonal and under 90 degree rotation with all ones connected only in a 101-111-101 pattern in any orientation.

1, 1, 1, 1, 1, 1, 1, 1, 3, 1, 5, 1, 9, 3, 20, 7, 76, 13, 246, 27, 866, 99, 3607, 409, 20611, 1589, 124905, 6601, 826121, 37581

Offset

1,9

Links

Table of n, a(n) for n=1..30.

Example

Maximal 9 X 9 example
.0.0.0.1.0.1.0.0.0
.0.0.0.1.1.1.0.0.0
.0.0.0.1.0.1.0.0.0
.1.1.1.0.0.0.1.1.1
.0.1.0.0.0.0.0.1.0
.1.1.1.0.0.0.1.1.1
.0.0.0.1.0.1.0.0.0
.0.0.0.1.1.1.0.0.0
.0.0.0.1.0.1.0.0.0

Crossrefs

Sequence in context: A262397 A155912 A050354 * A126213 A146935 A360756

Adjacent sequences: A146431 A146432 A146433 * A146435 A146436 A146437

Keyword

nonn

Author

R. H. Hardin

Status

approved