A146641 Number of n X n binary arrays symmetric under 180 degree rotation with all ones connected only in a 1010-1111-0100 pattern in any orientation.

1, 1, 1, 1, 1, 25, 49, 271, 1415, 7425, 56853, 745419, 7546933, 141434655, 2375191029, 64505224261

Offset

1,6

Links

Table of n, a(n) for n=1..16.

Example

Maximal 8 X 8 example
.0.0.0.0.0.1.0.1
.0.0.0.0.1.1.1.1
.0.1.0.0.0.0.1.0
.1.1.1.1.0.1.0.1
.1.0.1.0.1.1.1.1
.0.1.0.0.0.0.1.0
.1.1.1.1.0.0.0.0
.1.0.1.0.0.0.0.0

Crossrefs

Sequence in context: A020325 A108604 A046950 * A171590 A322434 A056981

Adjacent sequences: A146638 A146639 A146640 * A146642 A146643 A146644

Keyword

nonn

Author

R. H. Hardin, Nov 04 2008

Status

approved