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A302208
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Number of nX4 0..1 arrays with every element equal to 0, 2 or 3 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero.
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1
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1, 13, 5, 7, 18, 55, 172, 575, 1962, 6756, 23400, 81288, 283089, 987275, 3444621, 12023434, 41982749, 146612525, 512036344, 1788383898, 6246509941, 21818284060, 76209472929, 266195826556, 929812279542, 3247807389634, 11344517688838
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OFFSET
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1,2
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COMMENTS
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LINKS
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FORMULA
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Empirical: a(n) = 4*a(n-1) -3*a(n-2) +12*a(n-3) -21*a(n-4) -18*a(n-5) -16*a(n-6) +14*a(n-7) +21*a(n-8) +37*a(n-9) -6*a(n-10) +25*a(n-11) +62*a(n-12) -20*a(n-13) -7*a(n-14) -75*a(n-15) -76*a(n-16) -51*a(n-17) +57*a(n-18) +43*a(n-19) +35*a(n-20) +30*a(n-21) -35*a(n-22) -27*a(n-23) +10*a(n-24) +2*a(n-25) +6*a(n-26) -2*a(n-28) for n>32
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EXAMPLE
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Some solutions for n=5
..0..0..1..1. .0..0..1..0. .0..1..0..0. .0..0..1..1. .0..0..1..1
..0..0..1..1. .0..0..1..0. .0..1..0..0. .0..0..1..1. .0..0..1..1
..1..0..1..1. .1..1..1..1. .1..1..1..1. .1..0..0..1. .1..1..0..0
..0..0..1..1. .0..1..0..0. .0..0..1..0. .0..0..1..1. .1..1..0..0
..0..0..1..1. .0..1..0..0. .0..0..1..0. .0..0..1..1. .1..1..0..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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