A146017 Number of n X n binary arrays symmetric under horizontal and vertical 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, 1, 1, 1, 1, 29, 29, 297, 297, 3639, 3639, 84611, 84611, 2861167, 2861167, 210769267, 210769267, 22904472355, 22904472355

Offset

1,9

Links

Table of n, a(n) for n=1..22.

Example

Maximal 9 X 9 example
.1.0.1.1.0.1.1.0.1
.1.0.0.1.0.1.0.0.1
.1.0.0.1.0.1.0.0.1
.1.1.0.1.0.1.0.1.1
.0.0.0.0.0.0.0.0.0
.1.1.0.1.0.1.0.1.1
.1.0.0.1.0.1.0.0.1
.1.0.0.1.0.1.0.0.1
.1.0.1.1.0.1.1.0.1

Crossrefs

Sequence in context: A146423 A146129 A146040 * A210267 A210309 A165850

Adjacent sequences: A146014 A146015 A146016 * A146018 A146019 A146020

Keyword

nonn

Author

R. H. Hardin, Oct 26 2008

Status

approved