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A224723
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Number of (n+3) X 6 0..2 matrices with each 4 X 4 subblock idempotent.
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1
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2471, 2493, 3092, 3502, 3775, 4868, 6540, 8551, 10761, 13991, 18817, 25579, 34473, 46520, 63313, 86789, 119077, 163331, 224294, 308650, 425208, 585935, 807537, 1113408, 1535747, 2118724, 2923211, 4033478, 5565990, 7681386, 10601173
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OFFSET
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1,1
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LINKS
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FORMULA
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Empirical: a(n) = 3*a(n-1) - 2*a(n-2) - 2*a(n-3) + 4*a(n-4) - 3*a(n-5) + 2*a(n-7) - a(n-8) for n>10.
Empirical g.f.: x*(2471 - 4920*x + 555*x^2 + 4154*x^3 - 5445*x^4 + 4172*x^5 + 1601*x^6 - 3457*x^7 + 815*x^8 + 52*x^9) / ((1 - x)^3*(1 + x)*(1 - x - x^4)). - Colin Barker, Sep 04 2018
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EXAMPLE
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Some solutions for n=2:
..0..1..0..0..0..2....0..0..0..0..0..0....1..0..0..0..2..0....0..1..0..0..0..2
..0..1..0..0..0..0....1..1..1..1..1..2....1..0..0..0..2..0....0..1..0..0..0..1
..0..1..0..0..0..2....0..0..0..0..0..0....1..0..0..0..1..0....0..1..0..0..0..2
..0..1..0..0..0..1....0..0..0..0..0..0....0..0..0..0..1..0....0..2..0..0..0..1
..0..2..0..0..0..1....0..0..0..0..0..0....2..0..0..0..1..0....0..1..0..0..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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