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A366326
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G.f. satisfies A(x) = (1 + x) * (1 + x/A(x)^2).
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5
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1, 2, -3, 14, -78, 479, -3131, 21372, -150588, 1087057, -7998295, 59763129, -452257495, 3459109408, -26697940390, 207672518808, -1626400971710, 12813379464399, -101482102525511, 807524595076284, -6452856224076654, 51760509258982478, -416620859045829372
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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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a(n) = (-1)^(n-1) * Sum_{k=0..n} binomial(3*k-1,k) * binomial(n+k-2,n-k)/(3*k-1).
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PROG
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(PARI) a(n) = (-1)^(n-1)*sum(k=0, n, binomial(3*k-1, k)*binomial(n+k-2, n-k)/(3*k-1));
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CROSSREFS
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KEYWORD
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sign
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AUTHOR
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STATUS
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approved
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