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A317737
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Number of nX4 0..1 arrays with every element unequal to 2 or 3 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero.
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1
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0, 2, 3, 4, 14, 23, 35, 98, 213, 448, 1053, 2285, 5170, 11442, 25631, 57472, 127875, 286908, 640173, 1432260, 3202305, 7156889, 16008863, 35779725, 80013078, 178882627, 399942789, 894243714, 1999266125, 4470164997, 9994288714
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OFFSET
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1,2
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COMMENTS
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Column 4 of A317741.
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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) +2*a(n-2) +3*a(n-3) -2*a(n-4) +a(n-5) -6*a(n-6) +8*a(n-7) -16*a(n-8) -7*a(n-9) -17*a(n-10) +7*a(n-11) +5*a(n-12) +9*a(n-13) +3*a(n-14) +28*a(n-15) +16*a(n-16) +18*a(n-17) -5*a(n-18) -2*a(n-19) -3*a(n-20) -2*a(n-21) -a(n-22) +a(n-23) for n>26
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EXAMPLE
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Some solutions for n=5
..0..1..0..1. .0..1..0..1. .0..1..0..1. .0..1..0..0. .0..1..1..0
..1..0..0..0. .1..0..0..0. .1..0..0..1. .1..1..1..1. .1..0..0..1
..0..1..1..1. .0..0..1..1. .0..0..1..0. .0..1..1..0. .0..0..1..0
..1..1..1..0. .1..1..1..0. .1..1..1..0. .0..0..0..1. .1..1..1..0
..0..0..0..1. .0..0..0..1. .0..1..0..1. .1..0..1..0. .0..1..0..1
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CROSSREFS
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Cf. A317741.
Sequence in context: A333622 A019137 A333623 * A188533 A163128 A280924
Adjacent sequences: A317734 A317735 A317736 * A317738 A317739 A317740
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KEYWORD
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nonn
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AUTHOR
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R. H. Hardin, Aug 05 2018
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STATUS
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approved
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