A146826 Number of n X n binary arrays symmetric about main diagonal with all ones connected only in a 1000-1111-0100-0100 pattern in any orientation.

1, 1, 1, 1, 1, 3, 11, 27, 69, 315, 1713, 11493, 84155, 723421, 7696049, 106846827, 1733858135, 33633104443, 799782972413, 23215563898915, 806581387639407

Offset

1,6

Links

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

Example

Maximal 8 X 8 example
.0.0.0.0.0.0.0.0
.0.0.0.0.0.0.0.0
.0.0.0.0.0.0.0.1
.0.0.0.0.1.1.1.1
.0.0.0.1.0.0.1.0
.0.0.0.1.0.0.1.0
.0.0.0.1.1.1.0.0
.0.0.1.1.0.0.0.0

Crossrefs

Sequence in context: A372612 A147118 A147157 * A059400 A250223 A250271

Adjacent sequences: A146823 A146824 A146825 * A146827 A146828 A146829

Keyword

nonn

Author

R. H. Hardin, Nov 04 2008

Status

approved