Back to Minimum overlap problem

n = 8
f(x) = 0.089641067480915042for 0x < 1/4
f(x) = 0.463633234694070334for 1/4x < 2/4
f(x) = 0.608616277306427928for 2/4x < 3/4
f(x) = 0.838109420518586696for 3/4x ≤ 1
f(x) = f(2-x)for 1< x ≤ 2
Illustration
α(f) < 0.385071709487211768
 maximal for 1/4 ≤ |k| ≤ 3/4