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Numerators of the redundant Stern-Brocot structure; denominators=A152976.
3

%I #5 Mar 30 2012 18:51:00

%S 1,1,3,2,1,3,2,5,3,6,3,1,3,2,5,3,6,3,7,4,9,5,10,5,9,4,1,3,2,5,3,6,3,7,

%T 4,9,5,10,5,9,4,9,5,12,7,15,8,15,7,14,7,15,8,15,7,12,5,1,3,2,5,3,6,3,

%U 7,4,9,5,10,5,9,4,9,5,12,7,15,8,15,7,14,7,15,8,15,7,12,5,11,6,15,9,20,11,21

%N Numerators of the redundant Stern-Brocot structure; denominators=A152976.

%C The redundant Stern-Brocot structure is constructed row by row: insert between consecutive terms of the full Stern-Brocot tree their mediant (non-reduced), where the mediant of s/t and u/v = (s+u)/(t+v);

%C a(2^n-n+2*k) = A007305(2^(n-1)+k+2) for 0<=k<2^(n-1);

%C a(2^n-n+2*k-1) = A007305(2^(n-1)+k-1+2) + A007305(2^(n-1)+k+2) for 0<k<2^(n-1);

%C the graph of this structure describes an interesting ternary representation of the positive rational numbers;

%C A060188(k+2) = Sum(a(i): 2^k <= i < 2^(k+1)).

%D Milad Niqui, Formalising Exact Arithmetic, Ph.D. thesis, Radboud Universiteit Nijmegen, IPA Dissertation Series 2004-10, 2.6, p.65f .

%H Milad Niqui, <a href="http://www.cs.ru.nl/~milad/proefschrift/thesis.pdf">Formalising Exact Arithmetic</a>

%H <a href="/index/St#Stern">Index entries for sequences related to Stern's sequences</a>

%e [0/1] . . . . . . . . . . . . . . . . . . . . . . . . . . . [1/0]

%e .............................. 1/1

%e ............. 1/2 ............ 3/3 ............ 2/1

%e ..... 1/3 ... 3/6 .... 2/3 ... 5/5 ... 3/2 .... 6/3 ... 3/1

%e . 1/4 3/9 2/5 5/10 3/5 6/9 3/4 7/7 4/3 9/6 5/3 10/5 5/2 9/3 4/1.

%K frac,nonn,tabf

%O 1,3

%A _Reinhard Zumkeller_, Dec 22 2008