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A364523
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G.f. satisfies A(x) = 1 + x*A(x) + x^6*A(x)^6.
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6
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1, 1, 1, 1, 1, 1, 2, 8, 29, 85, 211, 463, 931, 1795, 3550, 7736, 18929, 49505, 130000, 330430, 804271, 1885675, 4327555, 9929515, 23224435, 55907251, 138016906, 345107296, 862546231, 2136402451, 5231163232, 12697101118, 30723857209, 74569942745
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OFFSET
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0,7
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COMMENTS
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Number of ordered trees with n edges and having nonleaf nodes of outdegrees 1 or 6. - Emanuele Munarini, Jul 11 2024
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LINKS
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FORMULA
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a(n) = Sum_{k=0..floor(n/6)} binomial(n,6*k) * binomial(6*k,k) / (5*k+1).
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PROG
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(PARI) a(n) = sum(k=0, n\6, binomial(n, 6*k)*binomial(6*k, k)/(5*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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