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A372012
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G.f. A(x) satisfies A(x) = 1/( 1 + x*(1 - 4*x*A(x))^(1/2) ).
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2
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1, -1, 3, -5, 17, -31, 119, -211, 937, -1483, 8015, -10187, 73369, -62193, 713907, -234857, 7358657, 1881661, 80117735, 69295469, 917837521, 1334044075, 11006114883, 21830065899, 137275956089, 333858963899, 1769128762419, 4940496514271, 23409778504937
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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) = (-1)^n * Sum_{k=0..n} 4^(n-k) * binomial(n,k) * binomial(k/2,n-k)/(n-k+1).
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PROG
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(PARI) a(n) = (-1)^n*sum(k=0, n, 4^(n-k)*binomial(n, k)*binomial(k/2, n-k)/(n-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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