A146031 Number of n X n binary arrays symmetric under horizontal reflection with all ones connected only in a 3X3 el 1,1 1,2 1,3 2,3 3,3 in any orientation.

1, 1, 1, 1, 1, 1, 47, 87, 827, 1813, 23847, 61833, 1905275, 6035973, 614447855, 2474833329, 318082536355, 1576923345267, 332168016129555, 2011400450726835, 916006897110162895, 6848186045213206995, 6424521065702879448173

Offset

1,7

Links

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

Example

Maximal 8 X 8 example
.1.1.1.0.0.1.1.1
.1.0.0.0.0.0.0.1
.1.0.0.0.0.0.0.1
.0.0.0.0.0.0.0.0
.0.0.0.0.0.0.0.0
.1.0.0.0.0.0.0.1
.1.0.0.0.0.0.0.1
.1.1.1.0.0.1.1.1

Crossrefs

Sequence in context: A190799 A246873 A033232 * A272879 A139968 A132451

Adjacent sequences: A146028 A146029 A146030 * A146032 A146033 A146034

Keyword

nonn

Author

R. H. Hardin, Oct 26 2008

Status

approved