A146433 Number of n X n binary arrays symmetric about both diagonal and antidiagonal with all ones connected only in a 101-111-101 pattern in any orientation.

1, 1, 1, 1, 1, 1, 1, 1, 3, 5, 9, 13, 25, 49, 124, 263, 846, 2209, 7594, 21663, 81736, 275021, 1243671, 4831201, 26082779, 118314435, 731456697, 3805948133, 26532655113, 159482402665

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: A133033 A145365 A306833 * A134672 A321024 A211389

Adjacent sequences: A146430 A146431 A146432 * A146434 A146435 A146436

Keyword

nonn

Author

R. H. Hardin

Status

approved