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A187956
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Half the number of (n+2) X 3 binary arrays with no 3 X 3 subblock having a sum equal to any horizontal or vertical neighbor 3 X 3 subblock sum.
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1
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256, 1408, 7744, 42592, 240064, 1353088, 7626496, 42683776, 238891456, 1337021536, 7498109248, 42049915264, 235818833152, 1321724569984, 7408042078528, 41520819604576, 232755657125056, 1304771833495936
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OFFSET
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1,1
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COMMENTS
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Column 1 of A187964.
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LINKS
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R. H. Hardin, Table of n, a(n) for n = 1..200
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FORMULA
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Empirical: a(n) = 4*a(n-1) + 9*a(n-2) - 36*a(n-3) + 144*a(n-4) + 324*a(n-5) + 729*a(n-6) - 2916*a(n-7) - 6561*a(n-8).
Empirical g.f.: 32*x*(8 + 12*x - 6*x^2 + 255*x^3 + 432*x^4 + 81*x^5 - 5346*x^6 - 8748*x^7) / ((1 - 4*x - 9*x^2)*(1 + 36*x^3 - 729*x^6)). - Colin Barker, Apr 26 2018
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EXAMPLE
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Some solutions for 4 X 3 with a(1,1)=0.
..0..1..1....0..0..1....0..1..1....0..1..0....0..0..1....0..1..0....0..1..0
..1..0..1....1..0..1....1..1..1....0..1..1....1..1..0....1..1..1....1..0..0
..1..1..1....1..1..1....1..1..1....1..0..1....1..0..0....0..0..0....1..0..0
..1..1..1....1..0..1....0..1..0....1..1..0....0..1..1....1..1..1....0..0..0
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CROSSREFS
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Cf. A187964.
Sequence in context: A237309 A188865 A187964 * A237225 A237219 A237951
Adjacent sequences: A187953 A187954 A187955 * A187957 A187958 A187959
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KEYWORD
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nonn
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AUTHOR
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R. H. Hardin, Mar 16 2011
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STATUS
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approved
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