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Search: id:A130550
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| A130550 |
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Denominators of partial sums for a series for 2*Zeta(2)/3 = (Pi^2)/9. |
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+0
4
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| 1, 12, 180, 1008, 8400, 118800, 75675600, 302702400, 15437822400, 26665329600, 3226504881600, 5708431713600, 964724959598400, 964724959598400, 46628373047256000, 340112838697632000, 98292610383615648000
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OFFSET
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1,2
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COMMENT
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Numerators are given in A130549.
For the rationals r(n):= 2*sum(1/(j^2*binomial(2*j,j)),j=1..n), n>=1, the van der Poorten reference and a W. Lang link see A130551.
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REFERENCES
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C. Elsner, On recurrence formulae for sums involving binomial coefficients, Fib. Q., 43 (No. 1, 2005), 31-45.
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FORMULA
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a(n)=denominator(r(n)), n>=1.
Denominator of (2/3)* Sum_{i=1..n} 1/(i^2*C(2*i,i)). - Wolfdieter Lang, Oct 07 2008
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CROSSREFS
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Cf. A112099, A112100, A112102, A112103, A130549.
Sequence in context: A099930 A052208 A045952 this_sequence A073975 A069685 A000515
Adjacent sequences: A130547 A130548 A130549 this_sequence A130551 A130552 A130553
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KEYWORD
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nonn,frac,easy
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AUTHOR
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Wolfdieter Lang (wolfdieter.lang(AT)physik.uni-karlsruhe.de) Jul 13 2007
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