A146629 Number of n X n binary arrays symmetric about main diagonal with all ones connected only in a 1010-1111-0010 pattern in any orientation.

1, 1, 1, 1, 1, 7, 21, 47, 215, 1109, 8005, 71755, 717641, 8603611, 133533027, 2609017895, 64328667073, 1958813665949, 72296633852443, 3294639375085767, 187627806470686453

Offset

1,6

Links

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

Example

Maximal 8 X 8 example
.0.0.1.0.1.0.0.0
.0.0.1.1.1.1.0.0
.1.1.0.0.1.0.1.0
.0.1.0.0.0.1.1.1
.1.1.1.0.0.0.1.0
.0.1.0.1.0.0.1.1
.0.0.1.1.1.1.0.0
.0.0.0.1.0.1.0.0

Crossrefs

Sequence in context: A212677 A146802 A147054 * A195965 A137182 A011927

Adjacent sequences: A146626 A146627 A146628 * A146630 A146631 A146632

Keyword

nonn

Author

R. H. Hardin, Nov 04 2008

Status

approved