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A235312
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Number of (n+1) X (1+1) 0..6 arrays with every 2 X 2 subblock having its diagonal sum differing from its antidiagonal sum by 7 (constant-stress 1 X 1 tilings).
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1
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112, 392, 1120, 3920, 11776, 41216, 128128, 448448, 1426432, 4992512, 16130560, 56456960, 184446976, 645564416, 2126645248, 7443258368, 24679432192, 86378012672, 287911321600, 1007689625600, 3373484670976, 11807196348416
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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) = 28*a(n-2) -252*a(n-4) +720*a(n-6).
Empirical g.f.: 8*x*(2 + 7*x)*(7 - 126*x^2 + 540*x^4) / ((1 - 6*x^2)*(1 - 10*x^2)*(1 - 12*x^2)). - Colin Barker, Oct 18 2018
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EXAMPLE
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Some solutions for n=4:
4 2 6 2 3 2 2 3 1 2 4 0 5 0 5 0 3 5 3 0
0 5 0 3 0 6 6 0 6 0 1 4 0 2 2 4 6 1 1 5
3 1 5 1 6 5 5 6 4 5 5 1 5 0 6 1 3 5 6 3
1 6 0 3 0 6 6 0 6 0 0 3 3 5 3 5 6 1 2 6
4 2 4 0 2 1 5 6 5 6 5 1 5 0 5 0 2 4 3 0
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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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