%N Abelian complexity function of A064990.
%C a(n) also equals the Abelian complexity function of A189718.
%H Nathan Fox, <a href="/A216197/a216197.py.txt">Python program to generate sequence</a>
%F a(1) = 2; a(3n) = a(n) + 2; a(3n-1) = a(n) + 1; a(3n+1) = a(n) + 1.
%Y Cf. A064990, A189718.
%A _Nathan Fox_, Mar 12 2013