e = {11, 2, 1, 8, 7, 14, 13, 4};
x = 4/15;
y = 15/4;
a1 = {};
a2 = {};
a3 = {};
a4 = {};
For[i = 1, i < 9, i++,
 AppendTo[a1, x/i];
 AppendTo[a2, y*i];
 AppendTo[a3, y/i];
 AppendTo[a4, x*i]
 ]
x = Denominator[
  a3](*to calculate a1 to a8, ie x=a1 or x=Numerator[a1] etc*)
x = e/a4(*to calculate f1 to f4*)
Total[x]
Mean[x]
Min[x]
Max[x]
CountDistinct[x]
CountDistinct[Differences[x]]
Differences[x]