A146042 Number of n X n binary arrays symmetric about both diagonal and antidiagonal with all ones connected only in a 2X4 tee 1,1 1,2 1,3 2,3 1,4 in any orientation.

1, 1, 1, 1, 1, 3, 5, 11, 21, 41, 165, 701, 2953, 12345, 51325, 344201, 2572877, 21631323, 180106811, 1718811817, 19639803327, 281005626019, 4302161174593, 75232261306781, 1397819874484453, 32083258430460691

Offset

1,6

Links

Table of n, a(n) for n=1..26.

Example

Maximal 8 X 8 example
.0.0.0.0.0.0.0.0
.0.0.1.1.1.1.0.0
.0.1.0.0.1.0.1.0
.0.1.0.0.0.1.1.0
.0.1.1.0.0.0.1.0
.0.1.0.1.0.0.1.0
.0.0.1.1.1.1.0.0
.0.0.0.0.0.0.0.0

Crossrefs

Sequence in context: A147243 A192664 A122997 * A291219 A284358 A283584

Adjacent sequences: A146039 A146040 A146041 * A146043 A146044 A146045

Keyword

nonn

Author

R. H. Hardin, Oct 26 2008

Status

approved