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A252726
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Number of (7+2) X (n+2) 0..3 arrays with every consecutive three elements in every row and diagonal having exactly two distinct values, and in every column and antidiagonal not having exactly two distinct values, and new values 0 upwards introduced in row major order.
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1
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257, 220, 224, 257, 288, 324, 373, 452, 512, 617, 768, 900, 1093, 1412, 1664, 2057, 2688, 3204, 3973, 5252, 6272, 7817, 10368, 12420, 15493, 20612, 24704, 30857, 41088, 49284, 61573, 82052, 98432, 123017, 163968, 196740, 245893, 327812, 393344
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OFFSET
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1,1
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LINKS
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R. H. Hardin, Table of n, a(n) for n = 1..210
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FORMULA
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Empirical: a(n) = -a(n-1) + 3*a(n-3) + 3*a(n-4) - 2*a(n-6) - 2*a(n-7) for n>9.
Empirical g.f.: x*(257 + 477*x + 444*x^2 - 290*x^3 - 886*x^4 - 720*x^5 - 232*x^6 + 144*x^7 + 16*x^8) / ((1 - x)*(1 + x)*(1 + x + x^2)*(1 - 2*x^3)). - Colin Barker, Dec 06 2018
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EXAMPLE
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Some solutions for n=4:
..0..1..1..0..1..1....0..1..1..0..1..1....0..1..0..0..1..0....0..0..1..0..0..2
..0..2..0..0..3..0....1..0..1..1..0..1....1..1..2..1..1..2....0..3..3..0..3..3
..0..0..2..0..0..3....2..2..1..2..2..1....3..1..1..2..1..1....0..1..0..0..1..0
..0..1..1..0..1..1....0..1..1..0..1..1....0..1..0..0..1..0....0..0..1..0..0..1
..0..3..0..0..2..0....1..0..1..1..0..1....1..1..3..1..1..2....0..3..3..0..3..3
..0..0..3..0..0..2....2..2..1..2..2..1....3..1..1..3..1..1....0..2..0..0..1..0
..0..1..1..0..1..1....3..1..1..0..1..1....0..1..0..0..1..0....0..0..2..0..0..1
..0..3..0..0..3..0....1..3..1..1..0..1....1..1..3..1..1..3....0..3..3..0..3..3
..0..0..3..0..0..3....2..2..1..2..2..1....2..1..1..3..1..1....0..2..0..0..2..0
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CROSSREFS
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Row 7 of A252719.
Sequence in context: A273775 A182912 A276233 * A260679 A043676 A296901
Adjacent sequences: A252723 A252724 A252725 * A252727 A252728 A252729
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KEYWORD
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nonn
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AUTHOR
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R. H. Hardin, Dec 20 2014
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STATUS
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approved
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