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A051737
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Number of 4 X n (0,1)-matrices with no consecutive 1's in any row or column.
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8
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1, 8, 41, 227, 1234, 6743, 36787, 200798, 1095851, 5980913, 32641916, 178150221, 972290957, 5306478436, 28961194501, 158061670175, 862654025422, 4708111537971, 25695485730239, 140238391149386, 765379824048327, 4177217595760125, 22798023012345528, 124424893212114297
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OFFSET
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0,2
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LINKS
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FORMULA
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From Yong Kong (ykong(AT)curagen.com), Dec 24 2000: (Start)
a(n) = 4*a(n - 1) + 9*a(n - 2) - 5*a(n - 3) - 4*a(n - 4) + a(n - 5);
G.f.: (1 + 4*x - 4*x^3 + x^4)/(1 - 4*x - 9*x^2 + 5*x^3 + 4*x^4 - x^5). (End)
a(n) = 2*a(n - 1) + 18*a(n - 2) + 9*a(n - 3) - 23*a(n - 4) - 2*a(n - 5) + 6*a(n - 6) - a(n - 7).
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MATHEMATICA
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LinearRecurrence[{4, 9, -5, -4, 1}, {1, 8, 41, 227, 1234}, 24] (* Jean-François Alcover, Nov 05 2017 *)
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PROG
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(PARI) Vec((1+4*x-4*x^3+x^4)/(1-4*x-9*x^2+5*x^3+4*x^4-x^5) + O(x^50)) \\ Michel Marcus, Sep 17 2014
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CROSSREFS
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KEYWORD
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easy,nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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