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A146021
Number of n X n binary arrays symmetric under 90 degree rotation with all ones connected only in a 2X4 el 1,1 1,2 1,3 1,4 2,4 with any orientation.
0
1, 1, 1, 1, 1, 3, 17, 33, 77, 271, 971, 3963, 20443, 99229, 615963, 4003277, 33415251, 283218519, 3003051651, 32410844251, 438884364075
OFFSET
1,6
EXAMPLE
Maximal 8 X 8 example
.1.0.0.0.1.1.1.1
.1.0.0.0.1.0.0.0
.1.0.0.0.0.0.0.0
.1.1.0.0.0.0.0.0
.0.0.0.0.0.0.1.1
.0.0.0.0.0.0.0.1
.0.0.0.1.0.0.0.1
.1.1.1.1.0.0.0.1
CROSSREFS
Sequence in context: A214093 A309744 A115355 * A146133 A297735 A266062
KEYWORD
nonn
AUTHOR
R. H. Hardin, Oct 26 2008
STATUS
approved