A146574 Number of n X n binary arrays symmetric about both diagonal and antidiagonal with all ones connected only in a 0100-0100-1111 pattern in any orientation.

1, 1, 1, 1, 1, 1, 3, 5, 11, 21, 43, 131, 425, 1453, 5677, 20565, 100203, 517949, 3251987, 21002085, 153166855, 1157817079, 10741996431, 104706915655

Offset

1,7

Links

Table of n, a(n) for n=1..24.

Example

Maximal 8 X 8 example
.0.0.0.1.1.1.1.0
.0.0.0.0.1.0.0.1
.0.0.0.0.1.0.0.1
.1.0.0.0.0.1.1.1
.1.1.1.0.0.0.0.1
.1.0.0.1.0.0.0.0
.1.0.0.1.0.0.0.0
.0.1.1.1.1.0.0.0

Crossrefs

Sequence in context: A077465 A283647 A283905 * A007873 A274938 A283603

Adjacent sequences: A146571 A146572 A146573 * A146575 A146576 A146577

Keyword

nonn

Author

R. H. Hardin, Nov 04 2008

Status

approved