A146251 Number of n X n binary arrays symmetric about main diagonal with all ones connected only in a 110-111-011 pattern in any orientation.

1, 1, 3, 5, 9, 19, 71, 265, 1031, 4533, 26975, 188011, 1487007, 13567107, 149156483, 1938922129, 29541083501, 528608677059, 11174794559755, 278126836279869, 8142808516685673, 280747197308433325, 11410125160644854247

Offset

1,3

Links

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

Example

Maximal 8 X 8 example
.0.1.1.0.0.1.1.0
.1.1.1.0.0.1.1.1
.1.1.0.1.1.0.1.1
.0.0.1.1.1.0.0.0
.0.0.1.1.0.0.0.0
.1.1.0.0.0.1.1.0
.1.1.1.0.0.1.1.1
.0.1.1.0.0.0.1.1

Crossrefs

Sequence in context: A147010 A146912 A146940 * A281732 A066777 A260353

Adjacent sequences: A146248 A146249 A146250 * A146252 A146253 A146254

Keyword

nonn

Author

R. H. Hardin

Status

approved