f(a) = -a log­₂a

f(1/2) = 0.5

f(1/3) = 0.526

f(2/3) = 0.390

f(1/4) = 0.5

f(2/4) = 0.5

f(3/4) = 0.311

f(1/5) = 0.464

f(2/5) = 0.529

f(3/5) = 0.442

f(4/5) = 0.258

f(1/6) = 0.431

f(2/6) = 0.528

f(3/6) = 0.5

f(4/6) = 0.39

f(5/6) = 0.219