A130552 - OEIS

%I #7 Nov 09 2019 16:27:41

%S 1,24,1080,60480,1512000,7128000,31783752000,254270016000,

%T 38903312448000,67196630592000,89438715317952000,9308101594176000,

%U 347648286440879424000,347648286440879424000,50409001533927516480000,735378375318472005120000,3612913957939652961154560000,18401938665227434437120000

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

%C 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.

%C Numerators are given in A130551.

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

%o (PARI) a(n) = denominator(2*sum(j=1, n, (-1)^(j-1)/(j^3*binomial(2*j,j)))); \\ _Michel Marcus_, Nov 09 2019

%Y Cf. A130551 (numerators).

%K nonn,frac,easy

%O 1,2

%A _Wolfdieter Lang_, Jul 13 2007

%E More terms from _Michel Marcus_, Nov 09 2019