A146842 Number of n X n binary arrays symmetric about main diagonal with all ones connected only in a 1001-1111-1000 pattern in any orientation.

1, 1, 1, 1, 1, 3, 13, 31, 85, 391, 2235, 16087, 124573, 1136363, 12958205, 185857105, 3266797811, 68594033643, 1733074438523, 53263262779599, 1999938243860711

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
.0.0.0.0.1.0.0.1
.0.0.0.0.1.1.1.1
.0.0.1.1.0.0.0.1
.0.0.0.1.0.0.0.0
.0.0.0.1.0.0.0.0
.0.0.1.1.1.0.0.0

Crossrefs

Sequence in context: A146259 A146174 A147134 * A146191 A058264 A242905

Adjacent sequences: A146839 A146840 A146841 * A146843 A146844 A146845

Keyword

nonn

Author

R. H. Hardin, Nov 04 2008

Status

approved