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A209378
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1/4 the number of (n+1) X 5 0..2 arrays with every 2 X 2 subblock having distinct edge sums.
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1
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32, 80, 156, 512, 1076, 4004, 8612, 33716, 73028, 291908, 633732, 2555588, 5552900, 22478852, 48859652, 198127364, 430707716, 1747864580, 3799906308, 15425772548, 33536978948, 136164892676, 296038014980, 1202040352772, 2613387280388
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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) = 3*a(n-1) + 12*a(n-2) - 42*a(n-3) - 24*a(n-4) + 156*a(n-5) - 48*a(n-6) - 168*a(n-7) + 112*a(n-8).
Empirical g.f.: 4*x*(8 - 4*x - 117*x^2 + 107*x^3 + 449*x^4 - 472*x^5 - 502*x^6 + 548*x^7) / ((1 - x)*(1 - 2*x)*(1 - 2*x^2)*(1 - 12*x^2 + 28*x^4)). - Colin Barker, Jul 09 2018
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EXAMPLE
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Some solutions for n=4:
..0..2..2..2..0....2..0..2..0..2....1..2..2..2..1....0..0..2..1..2
..0..1..0..1..0....1..0..1..0..1....0..0..1..0..0....2..1..2..0..2
..2..2..2..2..2....2..2..2..0..2....1..2..2..2..1....2..0..2..1..2
..0..1..0..1..0....1..0..1..0..1....0..0..1..0..0....2..1..2..0..2
..0..2..0..2..2....2..0..2..2..2....1..2..2..2..1....0..0..2..1..2
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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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