  Studying ceratin combinatorial properties of non-unique factorizations have
been a subject of recent literatures. Little is known about two combinatorial
invariants, namely the catenary degree and the tame degree, even in the case of
numerical monoids. In this paper we compute these invariants for a certain
class of numerical monoids generated by generalized arithmetic sequences. We
also show that the difference between the tame degree and the catenary degree
can be arbitrary large even if the number of minimal generators is fixed.
