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A361835
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a(n) = Sum_{k=0..n} (-1)^(n-k) * binomial(2*k,k) * binomial(n*k,n-k).
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5
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1, 2, 2, -10, -10, 242, -678, -7054, 88342, -207646, -6015904, 88310862, -312514816, -8847633338, 184252541514, -1269592841970, -17662739133178, 634109114537218, -7914500471718552, -18165019012117450, 2936604063787679650, -62899139815867627378
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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) = [x^n] 1/sqrt(1 - 4*x*(1-x)^n).
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PROG
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(PARI) a(n) = sum(k=0, n, (-1)^(n-k)*binomial(2*k, k)*binomial(n*k, n-k));
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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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