A146016 Number of n X n binary arrays symmetric under horizontal reflection with all ones connected only in a 2X4 el 1,1 1,2 1,3 1,4 2,4 with any orientation.

1, 1, 1, 1, 9, 13, 45, 77, 3815, 10077, 367067, 1220229, 95121107, 408666247, 73141896271, 405640563989, 139061624003805, 984575363624555, 877050699436657647, 8038693070040612523

Offset

1,5

Links

Table of n, a(n) for n=1..20.

Example

Maximal 8 X 8 example
.0.0.0.0.0.0.0.0
.0.0.0.0.0.0.0.0
.1.1.0.0.0.0.1.1
.1.0.0.0.0.0.0.1
.1.0.1.0.0.1.0.1
.1.0.1.0.0.1.0.1
.0.0.1.0.0.1.0.0
.0.1.1.0.0.1.1.0

Crossrefs

Sequence in context: A188343 A160117 A068984 * A146128 A146039 A287005

Adjacent sequences: A146013 A146014 A146015 * A146017 A146018 A146019

Keyword

nonn

Author

R. H. Hardin, Oct 26 2008

Status

approved