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A224661
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Number of n X n 0..4 matrices with each 2X2 subblock idempotent
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0
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5, 20, 98, 180, 412, 806, 1606, 3070, 5808, 10798, 19866, 36184
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OFFSET
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1,1
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COMMENTS
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LINKS
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FORMULA
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Empirical: a(n) = 6*a(n-1) -12*a(n-2) +5*a(n-3) +12*a(n-4) -12*a(n-5) -3*a(n-6) +6*a(n-7) -a(n-9) for n>10
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EXAMPLE
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Some solutions for n=3
..1..0..2....1..0..3....0..0..0....0..0..0....1..0..0....1..1..0....0..0..0
..1..0..1....1..0..1....0..0..0....0..0..0....0..0..0....0..0..0....0..0..0
..4..0..1....2..0..1....2..1..1....0..0..0....0..0..1....0..0..1....4..1..1
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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