A variant of Hofstadter's sequence and finite automata
  Following up on a paper of Balamohan, Kuznetsov, and Tanny, we analyze a variant of Hofstadter's Q-sequence and show it is 2-automatic. An automaton computing the sequence is explicitly given. 
J.-P. Allouche, J. Shallit
math.NT cs.DM cs.FL