errors of a top-octave generator IC, see https://hackaday.com/2018/05/24/ask-hackaday-diy-top-octave-generator/

notes.py

import math

# highest note frequency
c = 4186.01

# distance factor between two notes
f = pow(2, 1.0/12.0)

# show frequncies
ds = [ 239, 253, 268, 284, 301, 319, 338, 358, 379, 402, 426, 451 ]
for d in ds:
    x = 1.0e6 / d
    print("calculated: %4.2f, with division: %4.2f, error: %2.2f %%" % (c, x, 100.0 - (x / c) * 100.0))
    c = c / f