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A365123
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G.f. satisfies A(x) = (1 + x / (1 - x*A(x))^4)^2.
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1
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1, 2, 9, 44, 244, 1438, 8858, 56340, 367160, 2438934, 16453015, 112411836, 776258588, 5409237100, 37988571802, 268606426836, 1910584687932, 13661702623498, 98148312810335, 708092115326436, 5127976641997944, 37264674894021280, 271650189521574734
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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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If g.f. satisfies A(x) = (1 + x/(1 - x*A(x))^s)^t, then a(n) = Sum_{k=0..n} binomial(t*(n-k+1),k) * binomial(n+(s-1)*k-1,n-k)/(n-k+1).
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PROG
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(PARI) a(n, s=4, t=2) = sum(k=0, n, binomial(t*(n-k+1), k)*binomial(n+(s-1)*k-1, n-k)/(n-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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