%I
%S 1,2,3,3,3,4,4,5,4,4,5,5,5,4,5,5,6,6,6,6,5,5,6,5,6,7,5,5,7,6,7,6,6,6,
%T 6,6,6,6,6,6,5,6,7,8,7,7,7,7,7,6,7,6,7,7,7,7,6,7,8,7,7,7,7,7,7,7,6,7,
%U 6,8,8,7,7,8,8,7,8,7,7,7,6,6,8,7,7,7,8,8,8,7,7,7,8,8,7,8,8,8,7,8,8
%N Consider the weighted Farey tree A177405/A177407; a(n) = row at which the denominator 2n+1 first appears (assumes first row is labeled row 1).
%C Equals A177903 + 1. See that entry for further information.
%K nonn
%O 0,2
%A _N. J. A. Sloane_, Dec 16 2010
