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A112093
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Numerator of 3*Sum_{i=1..n} 1/(i^2*C(2*i,i)).
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5
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0, 3, 13, 197, 1105, 9211, 130277, 82987349, 331950131, 16929464521, 29241805241, 3538258509761, 6259995854281, 1057939300471201, 1057939300716589, 51133732870640471, 372975463296151087, 107789908892879155343, 51058377896658637853, 681986753565766904623961
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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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3*Sum_{i >= 1} 1/(i^2*C(2*i, i)) = zeta(2) = Pi^2/6.
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MAPLE
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0, 3/2, 13/8, 197/120, 1105/672, 9211/5600, 130277/79200, 82987349/50450400, ... -> Pi^2/6.
X:= [0, seq(3/(i^2*binomial(2*i, i)), i=1..20)]:
S:= ListTools:-PartialSums(X):
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PROG
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(PARI) a(n) = numerator(3*sum(i=1, n, 1/(i^2*binomial(2*i, i)))); \\ Michel Marcus, Mar 10 2016
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CROSSREFS
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KEYWORD
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nonn,frac
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AUTHOR
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STATUS
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approved
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