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Denominators of s(i) = s(i-1) - (1/i)*sign(s(i-1)) with s(1) = 1.
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%I #17 Jun 06 2021 10:56:10

%S 1,2,6,12,60,20,140,280,2520,2520,27720,27720,360360,360360,72072,

%T 144144,2450448,2450448,46558512,232792560,232792560,232792560,

%U 5354228880,5354228880,26771144400,26771144400,80313433200,80313433200,2329089562800,2329089562800

%N Denominators of s(i) = s(i-1) - (1/i)*sign(s(i-1)) with s(1) = 1.

%C Numerators are given in A203810. The first 14 terms coincide with those of A002805.

%H Hugo Pfoertner, <a href="/A203811/b203811.txt">Table of n, a(n) for n = 1..200</a>

%e See A203810.

%t nxt[{n_,a_}]:={n+1,a-1/(n+1) Sign[a]}; NestList[nxt,{1,1},30][[All,2]]//Denominator (* _Harvey P. Dale_, Jun 06 2021 *)

%Y Cf. A002805, A203810 (numerators), A203812.

%K nonn,frac

%O 1,2

%A _Hugo Pfoertner_ and _Rainer Rosenthal_, Jan 06 2012