Let D be an increasing sequence of positive integers, and consider the divisor functions: d(n,D)=.d|nd.D,d.n.1,d2(n,D)=.[d,.]|nd,..D,[d,.].n.1, whe re [d, .] = l.c.m.(d, .). A probabilistic argument is introduced to evaluate the series ..n=1.nd(n,D) and ..n=1.nd2(n,D)