A146058 Number of n X n binary arrays symmetric about both diagonal and antidiagonal with all ones connected only in a 2X3 U in any orientation.

1, 1, 1, 1, 1, 1, 3, 7, 13, 21, 51, 159, 577, 2001, 7625, 31703, 159573, 881761, 5519227, 36692597, 286423433, 2406566921, 23662937019, 247567053249, 2997634212141, 39099498214505, 595262340859501, 9726061577357237, 184962190180592957

Offset

1,7

Links

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

Example

Maximal 8 X 8 example
.0.0.0.1.1.0.0.0
.0.0.0.0.1.0.0.0
.0.0.0.1.1.0.0.0
.1.0.1.0.0.1.1.1
.1.1.1.0.0.1.0.1
.0.0.0.1.1.0.0.0
.0.0.0.1.0.0.0.0
.0.0.0.1.1.0.0.0

Crossrefs

Sequence in context: A147501 A147335 A147464 * A155354 A136219 A078582

Adjacent sequences: A146055 A146056 A146057 * A146059 A146060 A146061

Keyword

nonn

Author

R. H. Hardin, Oct 26 2008

Status

approved