%I #13 Mar 28 2021 09:31:48
%S 1,1,2,1,2,7,8,1,2,7,8,19,20,25,26,1,2,7,8,19,20,25,26,55,56,61,62,73,
%T 74,79,80,1,2,7,8,19,20,25,26,55,56,61,62,73,74,79,80,163,164,169,170,
%U 181,182,187,188,217,218,223,224,235,236,241,242
%N a(2^n+a) = a(2^(n-1)+a) [if 0 <= a < 2^(n-1)], 3^n-a(2^n-a) [if 2^(n-1) <= a < 2^n].
%C Cantor tree of endpoints. Row #R (with 2^R values), divided by 3^R, gives some endpoints of the Cantor set.
%H PlanetMath, <a href="https://planetmath.org/cantorset">Cantor Set</a>
%e 1
%e 1,2
%e 1,2,7,8
%e 1,2,7,8,19,20,25,26
%K nonn
%O 1,3
%A _Roger L. Bagula_, Jan 07 2006
%E Edited by _N. J. A. Sloane_, Jan 26 2006