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A213749
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Antidiagonal sums of the convolution array A213747.
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3
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1, 9, 46, 180, 603, 1827, 5164, 13878, 35905, 90189, 221274, 532584, 1261687, 2949255, 6815896, 15597738, 35389629, 79691985, 178258150, 396361980, 876609811, 1929380139, 4227858756, 9227469150, 20065550713, 43486544277, 93952410034, 202400334288
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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) = 9*a(n-1) - 33*a(n-2) + 63*a(n-3) - 66*a(n-4) + 36*a(n-5) - 8*a(n-6).
G.f.: x*(1 - 2*x^2) / ((1 - x)^3*(1 - 2*x)^3).
a(n) = (1/2)*((1+n)*(4-2^(2+n) + n + 2^(1+n)*n)). - Colin Barker, Oct 30 2017
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MATHEMATICA
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LinearRecurrence[{9, -33, 63, -66, 36, -8}, {1, 9, 46, 180, 603, 1827}, 30] (* Harvey P. Dale, May 16 2013 *)
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PROG
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(PARI) Vec(x*(1 - 2*x^2) / ((1 - x)^3*(1 - 2*x)^3) + O(x^30)) \\ Colin Barker, Oct 30 2017
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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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