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A036542
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a(n) = T(n, n), array T given by A047858.
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1
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1, 3, 11, 34, 93, 236, 571, 1338, 3065, 6904, 15351, 33782, 73717, 159732, 344051, 737266, 1572849, 3342320, 7077871, 14942190, 31457261, 66060268, 138412011, 289406954, 603979753, 1258291176, 2617245671, 5435817958, 11274289125, 23353884644, 48318382051
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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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a(n) = 3*n * 2^(n-1) - n + 1.
a(n) = 6*a(n-1)-13*a(n-2)+12*a(n-3)-4*a(n-4) for n>3.
G.f.: (1-3*x+6*x^2-5*x^3) / ((1-x)^2*(1-2*x)^2).
(End)
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PROG
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(PARI) Vec((1-3*x+6*x^2-5*x^3)/((1-x)^2*(1-2*x)^2) + O(x^40)) \\ Colin Barker, Feb 20 2016
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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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