A146417 Number of n X n binary arrays symmetric about both diagonal and antidiagonal with all ones connected only in a 1000-1111-1000 pattern in any orientation.

1, 1, 1, 1, 1, 1, 1, 1, 4, 7, 14, 21, 51, 123, 453, 1219, 4641, 13599, 63683, 242234, 1440301, 6546459, 44699492, 239296946, 1977082524, 12922743339, 130202512826, 1020385455911, 12242346882334

Offset

1,9

Links

Table of n, a(n) for n=1..29.

Example

Maximal 9 X 9 example
.0.0.0.0.0.1.0.0.0
.0.0.1.1.1.1.0.0.0
.0.1.0.0.0.1.0.0.0
.0.1.0.0.0.0.1.1.1
.0.1.0.0.0.0.0.1.0
.1.1.1.0.0.0.0.1.0
.0.0.0.1.0.0.0.1.0
.0.0.0.1.1.1.1.0.0
.0.0.0.1.0.0.0.0.0

Crossrefs

Sequence in context: A201272 A147440 A146678 * A008370 A291877 A048241

Adjacent sequences: A146414 A146415 A146416 * A146418 A146419 A146420

Keyword

nonn

Author

R. H. Hardin

Status

approved