A Sequence which arises in the hypothetical reproduction of a population of rabbits. Let the Substitution Map correspond to young rabbits growing old, and correspond to old rabbits producing young rabbits. Starting with 0 and iterating using String Rewriting gives the terms 1, 10, 101, 10110, 10110101, 1011010110110, .... The limiting sequence written as a Binary Fraction (Sloane's A005614), where denotes a Binary number (a number in base-2) is called the Rabbit Constant.
See also Rabbit Constant, Thue-Morse Sequence
References
Schroeder, M. Fractals, Chaos, Power Laws: Minutes from an Infinite Paradise. New York: W. H. Freeman, p. 55, 1991.
Sloane, N. J. A. Sequence
A005614
in ``The On-Line Version of the Encyclopedia of Integer Sequences.''
http://www.research.att.com/~njas/sequences/eisonline.html.