Back to Minimum overlap problem

n = 7
f(x) = 0.105078900636553360for 0x < 2/7
f(x) = 0.503514170485956264for 2/7x < 4/7
f(x) = 0.668195943454623334for 4/7x < 6/7
f(x) = 0.946421970845734084for 6/7x ≤ 1
f(x) = f(2-x)for 1< x ≤ 2
Illustration
α(f) < 0.386120220734884585
 maximal for 2/7 ≤ |k| ≤ 6/7