We divide infinite sequences of subword complexity 2n+1 into
four subclasses with respect to left and right special elements
and examine the structure of the subclasses with the help of Rauzy
graphs. Let k ≥ 2 be an integer. If the expansion in base k
of a number is an Arnoux-Rauzy word, then it belongs to Subclass I
and the number is known to be transcendental. We prove the
transcendence of numbers with expansions in the subclasses II and
III.