This paper extends some results of Allouche and Shallit for q-regular sequences to numeration systems in algebraic number fields and to linear numeration systems. We also construct automata that perform addition and multiplication by a fixed number. 1 Introduction A sequence is called q-automatic if its n-th term can be generated by a finite state machine from the q-ary digits of n. The concept of automatic sequences was introduced in 1969 and 1972 by Cobham [8, 9]. In 1979 Christol  (see also Christol, Kamae, Mend`es France and Rauzy ) discovered a nice arithmetic property of automatic sequences: a sequence with values in a finite field of characteristic p is p-automatic if and only if the corresponding power series is algebraic over the field of rational functions over this finite field. A brief survey on this subject is given in , see also . Some generalizations of this concept were studied in [27, 23, 24, 3], see also the survey . An automatic sequence has to t..