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%I #6 Jul 05 2023 02:59:32
%S 1,4,36,720,25200,10800,5821200,302702400,908107200,15437822400,
%T 3226504881600,248192683200,964724959598400,964724959598400,
%U 1607874932664000,186513492189024000,98292610383615648000,1605505432763232000,16808036375598275808000,124379469179427240979200
%N Denominators of partial sums of a certain series of inverse central binomial coefficients.
%C See A145564 for the numerators, a reference and a W. Lang link.
%F a(n)=denominator(r(n)), with the rationals (in lowest terms) r(n):=sum(1/(binomial(2*k,k)*(k+1)),k=0..n).
%e Rationals r(n) (in lowest terms):[1, 5/4, 47/36, 949/720, 33287/25200, 14273/10800, 7694047/5821200,...].
%Y Cf. A145564.
%K nonn,frac,easy
%O 0,2
%A _Wolfdieter Lang_, Oct 17 2008