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A365153
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G.f. satisfies A(x) = ( 1 + x*A(x)^2*(1 + x*A(x)) )^2.
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3
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1, 2, 11, 74, 563, 4604, 39524, 351322, 3205699, 29854250, 282615379, 2711494224, 26307568324, 257673017952, 2544420045432, 25303000558890, 253184833958403, 2547251287244918, 25752086767703969, 261480234091024906, 2665405840919762043
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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)^2*(1 + x*A(x))^s )^t, then a(n) = Sum_{k=0..n} binomial(t*(n+k+1),k) * binomial(s*k,n-k)/(n+k+1).
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PROG
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(PARI) a(n, s=1, t=2) = sum(k=0, n, binomial(t*(n+k+1), k)*binomial(s*k, 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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