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A146149
Number of n X n binary arrays symmetric about the diagonal and under 90 degree rotation with all ones connected only in an em 1,1 1,2 2,2 2,3 3,3 in any orientation.
0
1, 1, 1, 1, 1, 1, 3, 3, 7, 7, 17, 17, 57, 57, 295, 295, 1823, 1823, 12191, 12191, 109351, 109351, 1406131, 1406131, 21111023, 21111023, 390067193, 390067193, 9744306045, 9744306045
OFFSET
1,7
EXAMPLE
Maximal 8 X 8 example
.0.0.1.0.0.1.0.0
.0.1.1.0.0.1.1.0
.1.1.0.0.0.0.1.1
.0.0.0.0.0.0.0.0
.0.0.0.0.0.0.0.0
.1.1.0.0.0.0.1.1
.0.1.1.0.0.1.1.0
.0.0.1.0.0.1.0.0
CROSSREFS
Sequence in context: A226781 A147144 A152113 * A263795 A070925 A146687
KEYWORD
nonn
AUTHOR
R. H. Hardin, Oct 27 2008
STATUS
approved