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A145949
Number of n X n binary arrays symmetric under 90-degree rotation with all ones connected in a 3 X 2 elbow 1,1 1,2 1,3 2,3 in any orientation.
0
1, 1, 1, 1, 3, 15, 35, 85, 321, 1353, 7451, 43415, 311247, 2524635, 23996463, 265026943, 3465054275, 52737773951, 953864284885, 19856088270267, 488084993258793
OFFSET
1,5
EXAMPLE
Maximal 8 X 8 example:
1 1 0 0 0 1 1 1
1 0 1 0 1 0 0 1
1 0 1 0 1 1 1 0
0 1 1 0 0 0 0 0
0 0 0 0 0 1 1 0
0 1 1 1 0 1 0 1
1 0 0 1 0 1 0 1
1 1 1 0 0 0 1 1
CROSSREFS
Sequence in context: A000466 A241237 A338351 * A015809 A293995 A015715
KEYWORD
nonn
AUTHOR
R. H. Hardin, Oct 25 2008
STATUS
approved