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A120997 Denominators of partial sums of Catalan numbers scaled by powers of 1/9. 1

%I

%S 1,9,81,729,6561,19683,177147,1594323,43046721,387420489,3486784401,

%T 31381059609,282429536481,2541865828329,2541865828329,22876792454961,

%U 205891132094649,5559060566555523,50031545098999707

%N Denominators of partial sums of Catalan numbers scaled by powers of 1/9.

%C Numerators are given under A120996.

%C See A120996 for details and a W. Lang link found there for the definition of four p-families of such scaled Catalan sums.

%F a(n)=denominator(r(n)) with r(n) := rI(p=1,n) = sum(C(k)/L(2)^(2*k),k=0..n), with Lucas L(2)=3 and C(k):=A000108(k) (Catalan).

%K nonn,frac,easy

%O 0,2

%A _Wolfdieter Lang_, Aug 16 2006

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Last modified May 29 03:06 EDT 2020. Contains 334696 sequences. (Running on oeis4.)