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A145970
Number of n X n binary arrays symmetric under 90-degree rotation with all ones connected only in a 1 X 5 or 5 X 1 block.
0
1, 1, 1, 1, 1, 1, 4, 7, 15, 33, 90, 201, 647, 1861, 7123, 23236, 101280, 390759, 2050696, 9515925, 59455120, 328131409, 2431442671, 15797747304, 137926288897, 1064505557777
OFFSET
1,7
EXAMPLE
Maximal 8 X 8 example:
0 0 0 0 0 0 1 0
1 1 1 1 1 0 1 0
0 0 0 0 0 0 1 0
0 1 0 0 0 0 1 0
0 1 0 0 0 0 1 0
0 1 0 0 0 0 0 0
0 1 0 1 1 1 1 1
0 1 0 0 0 0 0 0
CROSSREFS
Sequence in context: A131935 A119749 A201498 * A232048 A145795 A173657
KEYWORD
nonn
AUTHOR
R. H. Hardin, Oct 25 2008
STATUS
approved