%I #9 Jul 03 2023 08:02:02
%S 2,3,60,84,126,2772,72072,360360,1225224,23279256,11639628,503217,
%T 13385572200,2007835830,465817912560,2888071057872,627841534320,
%U 2489716429200,534293145706320,18423901576080,4381203794791824,941958815880242160,261655226633400600
%N Denominators of partial sums of the alternating series of inverse central binomial coefficients.
%C See A145375 for the numerators, references and a W. Lang link.
%F a(n) = denominator(r(n)), with the rationals (in lowest terms) r(n) := Sum_{k=1..n} (-1)^(k+1)/binomial(2*k,k).
%e Rationals r(n) (in lowest terms): [1/2, 1/3, 23/60, 31/84, 47/126, 1031/2772, 26827/72072, ...].
%Y Cf. A145375, A145557/A145558.
%K nonn,frac,easy
%O 1,1
%A _Wolfdieter Lang_, Oct 17 2008, Nov 17 2008, Nov 25 2008