A130552 Denominators of partial sums for a series of (4/5)*Zeta(3).

1, 24, 1080, 60480, 1512000, 7128000, 31783752000, 254270016000, 38903312448000, 67196630592000, 89438715317952000, 9308101594176000, 347648286440879424000, 347648286440879424000, 50409001533927516480000, 735378375318472005120000, 3612913957939652961154560000, 18401938665227434437120000

Offset: 1

Author

Wolfdieter Lang, Jul 13 2007

Keywords

• nonn
• frac
• easy

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.

Crossrefs

Cf. A130551 (numerators).

Programs

PARI

a(n) = denominator(2*sum(j=1, n, (-1)^(j-1)/(j^3*binomial(2*j,j)))); \\ Michel Marcus, Nov 09 2019

Formula

a(n) = denominator(r(n)), n >= 1.

Extensions

More terms from Michel Marcus, Nov 09 2019