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A180764
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Half the number of nX4 binary arrays with each element equal to at least one neighbor
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1
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2, 34, 390, 4475, 52186, 606546, 7053923, 82032712, 953982820, 11094190209, 129018028226, 1500393683522, 17448578663219, 202915341402216, 2359770191311572, 27442554696574793, 319138622503858354
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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) = 9*a(n-1) + 35*a(n-2) - 29*a(n-3) - 256*a(n-4) - 120*a(n-5) + 695*a(n-6) + 579*a(n-7) - 949*a(n-8) - 1076*a(n-9) + 485*a(n-10) + 1488*a(n-11) + 588*a(n-12) - 857*a(n-13) - 368*a(n-14) - 73*a(n-15) - 52*a(n-16) + 26*a(n-17) + 14*a(n-18) + 12*a(n-19) - 4*a(n-20)
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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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