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A130552
Denominators of partial sums for a series of (4/5)*Zeta(3).
2
1, 24, 1080, 60480, 1512000, 7128000, 31783752000, 254270016000, 38903312448000, 67196630592000, 89438715317952000, 9308101594176000, 347648286440879424000, 347648286440879424000, 50409001533927516480000, 735378375318472005120000, 3612913957939652961154560000, 18401938665227434437120000
OFFSET
1,2
COMMENTS
For the rationals r(n) := 2*Sum_{j=1..n} ((-1)^(j-1))/((j^3)*binomial(2*j,j)), n >= 1, the van der Poorten reference and a W. Lang link see A130551.
Numerators are given in A130551.
FORMULA
a(n) = denominator(r(n)), n >= 1.
PROG
(PARI) a(n) = denominator(2*sum(j=1, n, (-1)^(j-1)/(j^3*binomial(2*j, j)))); \\ Michel Marcus, Nov 09 2019
CROSSREFS
Cf. A130551 (numerators).
Sequence in context: A112010 A278650 A046906 * A374885 A160260 A268149
KEYWORD
nonn,frac,easy
AUTHOR
Wolfdieter Lang, Jul 13 2007
EXTENSIONS
More terms from Michel Marcus, Nov 09 2019
STATUS
approved