For α∈ (0,1) and x∈ [0,π, we define S
(x,α) = 1 and
Also, we set, for α∈ (0,1),
where it is agreed that infØ =∞. It is shown in this paper that
and 8≤ N(α)<∞ if α0<α<α*, where α*:=0.33542. . . is the unique solution α∈ (0,1) of the equation
while α0= 0.308443. . . is the unique solution α∈ (0,1) of the equation
In the case α*<α<1, this extends a result of Brown, Wang and Wilson (1993).