A146219 Number of n X n binary arrays symmetric about main diagonal with all ones connected only in a 101-111-010 pattern in any orientation.

1, 1, 1, 1, 3, 9, 20, 63, 272, 1557, 10412, 77761, 729051, 8641753, 126757272, 2289847876, 50015283552, 1327280079169, 43398915228962, 1753679030593542, 87293853894564783, 5311141506545315135, 394710940436034575590

Offset

1,5

Links

Table of n, a(n) for n=1..23.

Example

Maximal 8 X 8 example
.0.0.0.1.1.0.0.0
.0.0.1.1.0.0.0.0
.0.1.0.1.1.0.0.0
.1.1.1.0.0.1.0.1
.1.0.1.0.0.1.1.1
.0.0.0.1.1.0.1.0
.0.0.0.0.1.1.0.0
.0.0.0.1.1.0.0.0

Crossrefs

Sequence in context: A151420 A196294 A196212 * A197403 A305618 A377947

Adjacent sequences: A146216 A146217 A146218 * A146220 A146221 A146222

Keyword

nonn

Author

R. H. Hardin

Status

approved