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%I #10 Jul 03 2023 08:02:22
%S 1,20,28,168,9240,10010,30030,4084080,2351440,2351440,594914320,
%T 1487285800,2677114440,22181805360,67415290800,404491744800,
%U 48134517631200,197886350261600,593659050784800,24340021082176800,15168418935269600,136515770417426400
%N Denominators of partial sums of a certain series of inverse central binomial coefficients.
%C See A145566 for the numerators, a reference and a W. Lang link.
%F a(n) = denominator(r(n))/6, with the rationals (in lowest terms) r(n) := Sum_{k=2..n} 1/(binomial(2*k,k)*(k-1)), n >= 2.
%e Rationals 6*r(n) (in lowest terms): [1, 23/20, 33/28, 199/168, 10957/9240, 11873/10010, 35621/30030, 4844519/4084080, ...].
%Y Cf. A145566.
%K nonn,frac,easy
%O 2,2
%A _Wolfdieter Lang_, Oct 17 2008, Oct 28 2008