A word has a square if it contains two consecutive occurrences of the same factor. For an alphabet of size k ≥ 3, we ask for the limit lim_{n → ∞} S(n)/n, where S(n) denotes the number of squarefree words of length n. The problem is most interesting in the case of k = 3, i.e., of three letters.

-- JeffreyShallit - 13 Jul 2011