%I #2 Mar 31 2012 13:20:12
%S 1,8,32,512,2048,16384,65536,2097152,8388608,67108864,268435456,
%T 4294967296,17179869184,137438953472,549755813888,35184372088832,
%U 140737488355328,1125899906842624,4503599627370496,72057594037927936
%N Denominators of partial sums of Catalan numbers scaled by powers of 1/8.
%C Numerators are given under A120780.
%C The listed numbers coincide with denominators of sum(C(k)/(-8)^k,k=0..n). For the numerators see A120789. In general these denominators may be different. See e.g. A120783 versus A120793 and A120787 versus A120796.
%F a(n)=denominator(r(n)), with the rationals r(n):=sum(C(k)/8^k,k=0..n) with C(k):=A000108(k) (Catalan numbers).
%K nonn,easy,frac
%O 0,2
%A _Wolfdieter Lang_, Jul 20 2006
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