A146060 Number of n X n binary arrays symmetric under 90 degree rotation with all ones connected only in a 2X3 U in any orientation.

1, 1, 1, 1, 1, 5, 15, 27, 53, 153, 487, 1719, 7415, 32545, 166197, 903303, 5463687, 37085195, 288519629, 2455679981, 24371430209, 259645240127, 3154594586943, 41721327840785, 629945561496623

Offset

1,6

Links

Table of n, a(n) for n=1..25.

Example

Maximal 8 X 8 example
.1.1.0.0.0.1.0.1
.0.1.0.0.0.1.1.1
.1.1.0.0.0.0.0.0
.0.0.0.0.0.0.0.0
.0.0.0.0.0.0.0.0
.0.0.0.0.0.0.1.1
.1.1.1.0.0.0.1.0
.1.0.1.0.0.0.1.1

Crossrefs

Sequence in context: A339567 A067533 A110343 * A076843 A285406 A129393

Adjacent sequences: A146057 A146058 A146059 * A146061 A146062 A146063

Keyword

nonn

Author

R. H. Hardin, Oct 26 2008

Status

approved