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A365136
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G.f. satisfies A(x) = (1 + x*A(x)/(1 - x*A(x))^3)^3.
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1
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1, 3, 21, 172, 1563, 15141, 153240, 1601160, 17140686, 187026210, 2072333697, 23255417925, 263757940688, 3018654757212, 34817822871933, 404324843585061, 4723248984803013, 55467143334798210, 654435356605769574, 7753961433310798095, 92220463998917459652
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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*A(x)/(1 - x*A(x))^s)^t, then a(n) = (1/(n+1)) * Sum_{k=0..n} binomial(t*(n+1),k) * binomial(n+(s-1)*k-1,n-k).
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PROG
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(PARI) a(n, s=3, t=3) = sum(k=0, n, binomial(t*(n+1), k)*binomial(n+(s-1)*k-1, n-k))/(n+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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