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A224663
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Number of n X n 0..6 matrices with each 2X2 subblock idempotent
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0
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7, 28, 162, 268, 596, 1118, 2166, 4038, 7488, 13686, 24818, 44640, 79796, 141848, 250966, 442168, 776152, 1357850, 2368298, 4119186
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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..1..2....1..1..6....1..1..4....0..0..0....0..1..0....1..1..0....1..0..3
..0..0..0....0..0..0....0..0..0....0..0..0....0..1..0....0..0..0....1..0..1
..2..1..1....3..1..1....6..1..1....4..1..1....0..1..0....0..0..1....2..0..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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