A146845 Number of n X n binary arrays symmetric under 90 degree rotation with all ones connected only in a 1001-1111-1000 pattern in any orientation.

1, 1, 1, 1, 1, 1, 5, 13, 35, 61, 141, 427, 1351, 4209, 19211, 75163, 402147, 1986547, 12595631, 74795099, 557304499

Offset

1,7

Links

Table of n, a(n) for n=1..21.

Example

Maximal 8 X 8 example
.0.0.0.0.1.1.1.0
.1.0.0.1.0.1.0.0
.1.1.1.1.0.1.0.0
.1.0.0.0.0.1.1.0
.0.1.1.0.0.0.0.1
.0.0.1.0.1.1.1.1
.0.0.1.0.1.0.0.1
.0.1.1.1.0.0.0.0

Crossrefs

Sequence in context: A092647 A171262 A006561 * A192310 A167710 A229924

Adjacent sequences: A146842 A146843 A146844 * A146846 A146847 A146848

Keyword

nonn

Author

R. H. Hardin, Nov 04 2008

Status

approved