%I A005812 M0111
%S A005812 0,1,2,1,2,3,2,3,2,1,2,3,2,3,4,3,4,3,2,3,4,3,4,3,2,3,2,1,2,3,2,3,4,3,4,
               3,
%T A005812 2,3,4,3,4,5,4,5,4,3,4,5,4,5,4,3,4,3,2,3,4,3,4,5,4,5,4,3,4,5,4,5,4,3,4,
               3,
%U A005812 2,3,4,3,4,3,2,3,2,1,2,3,2,3,4,3,4,3,2,3,4,3,4,5,4,5,4,3,4,5,4,5,4,3
%N A005812 Weight of balanced ternary representation of n.
%D A005812 Flajolet and Ramshaw, A note on Gray code..., SIAM J. Comput. 9 (1980), 
               142-158.
%D A005812 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, 
               Academic Press, 1995 (includes this sequence).
%H A005812 Michael Gilleland, <a href="selfsimilar.html">Some Self-Similar Integer 
               Sequences</a>
%F A005812 a(3n)=a(n), a(3n+1)=a(n)+1, a(9n+2)=a(n)+2, a(9n+5)=a(3n+2)+1, a(9n+8)=a(3n+2).
%F A005812 a(n) = sum{k>0, floor(|2*sin(n*pi/3^k)|)} - T. Suzuki (suzuki(AT)scio.co.jp), 
               Sep 10 2006
%o A005812 (Lisp) (defun btw (n) (if (= n 0) 0 (multiple-value-bind (q r) (round 
               n 3) (+ (abs r) (btw q)))))
%o A005812 (PARI) a(n)=local(q); if(n<=0,0,q=round(n/3); abs(n-3*q)+a(q))
%Y A005812 Sequence in context: A147784 A051329 A105499 this_sequence A136625 A086520 
               A012265
%Y A005812 Adjacent sequences: A005809 A005810 A005811 this_sequence A005813 A005814 
               A005815
%K A005812 easy,nonn,nice
%O A005812 0,3
%A A005812 N. J. A. Sloane (njas(AT)research.att.com), Jeffrey Shallit. Additional 
               terms from Allan Wechsler (acw(AT)alum.mit.edu)