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A213755
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Antidiagonal sums of the convolution array A213753.
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3
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1, 9, 44, 160, 491, 1355, 3486, 8546, 20245, 46773, 106048, 236980, 523535, 1145935, 2489202, 5372534, 11532633, 24639513, 52426420, 111146280, 234877811, 494924179, 1040183174, 2181033290, 4563397341, 9529452605
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OFFSET
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1,2
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LINKS
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FORMULA
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a(n) = (1/6)*(84 - 21*2^(n+2) + 23*n + 9*n*2^(n+2) - 3*n^2 - 2*n^3).
a(n) = 8*a(n-1) - 26*a(n-2) + 44*a(n-3) - 41*a(n-4) + 20*a(n-5) - 4*a(n-6).
G.f.: f(x)/g(x), where f(x) = x*(1 + x - 2*x^2 - 2*x^3) and g(x) = (1 - x)^4 * (1 - 2*x)^2.
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MATHEMATICA
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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STATUS
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approved
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