A146728 Number of n X n binary arrays symmetric under 90 degree rotation with all ones connected only in a 1101-0111 pattern in any orientation.

1, 1, 1, 1, 1, 3, 13, 31, 59, 133, 487, 1853, 8419, 38423, 183353, 1033531, 6717069, 50468649, 417543651, 3765006993, 38269269195, 435116516817

Offset

1,6

Links

Table of n, a(n) for n=1..22.

Example

Maximal 8 X 8 example
.0.0.0.1.1.1.0.0
.0.0.1.1.0.1.0.0
.1.1.0.0.0.0.1.0
.1.0.0.0.0.0.1.1
.1.1.0.0.0.0.0.1
.0.1.0.0.0.0.1.1
.0.0.1.0.1.1.0.0
.0.0.1.1.1.0.0.0

Crossrefs

Sequence in context: A387623 A051939 A257764 * A082709 A387622 A154833

Adjacent sequences: A146725 A146726 A146727 * A146729 A146730 A146731

Keyword

nonn

Author

R. H. Hardin, Nov 04 2008

Status

approved