A146284 Number of n X n binary arrays symmetric about both diagonal and antidiagonal with all ones connected only in a 111-110-111 pattern in any orientation.

1, 1, 1, 1, 1, 1, 1, 1, 5, 9, 17, 25, 55, 133, 419, 1009, 4455, 14333, 61219, 207501, 982915, 4258653, 26235061, 130258871, 1014665059, 6176852821

Offset

1,9

Links

Table of n, a(n) for n=1..26.

Example

Maximal 9 X 9 example
.0.0.0.1.0.1.0.0.0
.0.0.0.1.1.1.0.0.0
.0.0.0.1.1.1.0.0.0
.1.1.1.0.0.0.1.1.1
.0.1.1.0.0.0.1.1.0
.1.1.1.0.0.0.1.1.1
.0.0.0.1.1.1.0.0.0
.0.0.0.1.1.1.0.0.0
.0.0.0.1.0.1.0.0.0

Crossrefs

Sequence in context: A351837 A089109 A100449 * A175543 A200078 A190806

Adjacent sequences: A146281 A146282 A146283 * A146285 A146286 A146287

Keyword

nonn

Author

R. H. Hardin

Status

approved