The purpose of
this paper is to prove the following theorem. Suppose that for u ≥ n0, g(u)
and d(u) are positive functions such that ud(u) is nondecreasing and (i)
∑n−1g(n)d(n) < ∞. Then the series ∑d(n)An(x) is summable |C,1|, if the
following hold: