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A360709
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Expansion of Sum_{k>=0} (x^3 / (1 - k*x))^k.
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4
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1, 0, 0, 1, 1, 1, 2, 5, 13, 34, 90, 247, 720, 2256, 7568, 26814, 98982, 377541, 1484254, 6021789, 25271173, 109850447, 494355359, 2298362532, 11008133629, 54175202125, 273460921605, 1414449612648, 7494262602464, 40669492399396
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OFFSET
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0,7
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LINKS
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FORMULA
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a(n) = Sum_{k=1..floor(n/3)} k^(n-3*k) * binomial(n-2*k-1,k-1) for n > 0.
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PROG
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(PARI) my(N=30, x='x+O('x^N)); Vec(sum(k=0, N, (x^3/(1-k*x))^k))
(PARI) a(n) = if(n==0, 1, sum(k=1, n\3, k^(n-3*k)*binomial(n-2*k-1, k-1)));
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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