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A146059
Number of n X n binary arrays symmetric about the diagonal and under 90 degree rotation with all ones connected only in a 2X3 U in any orientation.
0
1, 1, 1, 1, 1, 1, 3, 1, 5, 1, 11, 5, 41, 13, 189, 31, 927, 133, 5603, 759, 45359, 5033, 469791, 38887, 5816617, 382421, 90000163, 4832387, 1751237935, 75700651
OFFSET
1,7
EXAMPLE
Maximal 9 X 9 example
.0.0.0.0.0.0.0.0.0
.0.0.0.1.0.1.0.0.0
.0.0.0.1.1.1.0.0.0
.0.1.1.0.0.0.1.1.0
.0.0.1.0.0.0.1.0.0
.0.1.1.0.0.0.1.1.0
.0.0.0.1.1.1.0.0.0
.0.0.0.1.0.1.0.0.0
.0.0.0.0.0.0.0.0.0
CROSSREFS
Sequence in context: A330773 A112031 A146285 * A046531 A289310 A160085
KEYWORD
nonn
AUTHOR
R. H. Hardin, Oct 26 2008
STATUS
approved