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A372136
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G.f. A(x) satisfies A(x) = 1/( 1 - x*A(x)^2*(1 + 9*x*A(x))^(1/3) ).
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2
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1, 1, 6, 24, 199, 1023, 9363, 53724, 514422, 3147234, 30860724, 197222004, 1959430572, 12936907792, 129445924524, 877093068720, 8806256385699, 60967636162677, 612785441368254, 4321431024295452, 43413113117835945, 311142782601086949, 3120889714454477613
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OFFSET
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0,3
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LINKS
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FORMULA
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a(n) = Sum_{k=0..n} 9^(n-k) * binomial(n+2*k,k) * binomial(k/3,n-k)/(n+k+1).
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PROG
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(PARI) a(n) = sum(k=0, n, 9^(n-k)*binomial(n+2*k, k)*binomial(k/3, 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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