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A056015
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a(n) = 6*a(n-1) - 5*a(n-2) - 4*a(n-3) - 3*a(n-4) + 2*a(n-5) + a(n-6), with a(0)=...=a(4)=0, a(5)=1.
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4
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0, 0, 0, 0, 0, 1, 6, 31, 152, 730, 3480, 16542, 78544, 372779, 1768958, 8393741, 39827472, 188975588, 896658432, 4254492236, 20186832928, 95783024581, 454473817254, 2156399264651, 10231739547432, 48547824776670, 230350985294584, 1092975362559562
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OFFSET
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0,7
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COMMENTS
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With a(0)=0, a(1)=1, a(2)=1, a(3)=2, a(4)=4, a(5)=7, this recurrence produces a(n) = A000073(n+1) (tribonacci numbers).
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LINKS
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FORMULA
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O.g.f.: -x^5/((x^3+x^2-5*x+1)*(x^3+x^2+x-1)). - R. J. Mathar, Nov 23 2007
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CROSSREFS
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KEYWORD
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nonn,easy,changed
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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