p[n_]  :=  
      Graphics[{PointSize[ .03],  Table[Point[{1/k, 0}], {k, 1, n}]}];

l =  Plot[If[x < 1/6, 0, 1], {x, 0, 1}]

l2 =  Plot[1, {x, 0, 1}, PlotRange -> {-0.02, 1.02}]

\(\(c[n_]\  := \ 
      Graphics[{GrayLevel[1], Table[Disk[{1/k, 1},  .015], {k, 1, n}], 

          GrayLevel[0], \ Table[Circle[{1/k, 1},  .015], {k, 1, n}]}]; \)\)

Show[l, p[6], c[6], PlotLabel -> Subscript[s, n],  AspectRatio -> 1,  
      Ticks -> False]

Show[l2, p[6], c[6], PlotLabel -> Subscript[t, n],  AspectRatio -> 1, 
       Ticks -> False]

b6  =  Sum[1/(6 + k),  {k, 1, 6}] // N

e6  =  1/(2 6) // N

a6  =  b6  +  e6/2

c6  =  b6  +  e6

Log[2] // N

%  -  a6

\(\)