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%I #14 Mar 07 2020 01:14:16
%S 0,1,2,3,6,4,10,15,12,5,14,24,21,28,40,35,20,6,18,33,30,44,65,60,36,
%T 45,84,104,77,70,88,63,30,7,22,42,39,60,90,85,52,70,133,168,126,119,
%U 152,112,55,66,144,209,170,198,273,228,126,117,204,234,165,130,154,99,42,8
%N Product of numerator and denominator of fractions in Farey tree A007305/A007306.
%C Sum of reciprocals of each row (n > 1) equals 1/2. E.g., 1/3 + 1/6, 1/4 + 1/10 + 1/15 + 1/12 and so on. The link to cut-the-knot gives credit to Pierre Lamothe for this observation. - _Joshua Zucker_, May 11 2006
%D J. C. Lagarias, Number Theory and Dynamical Systems, pp. 35-72 of S. A. Burr, ed., The Unreasonable Effectiveness of Number Theory, Proc. Sympos. Appl. Math., 46 (1992). Amer. Math. Soc.
%H Ivan Neretin, <a href="/A049449/b049449.txt">Table of n, a(n) for n = 0..4096</a>
%H Alexander Bogomolny, <a href="http://www.cut-the-knot.org/blue/Stern.shtml">Cut-the-knot on Stern-Brocot trees</a>
%F A007305*A007306.
%Y See comment in A119272.
%K nonn,easy,tabf
%O 0,3
%A _N. J. A. Sloane_
%E More terms from Megan Wawro (s1095813(AT)cedarville.edu)
%E More terms from _Joshua Zucker_, May 11 2006
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