There is an art-form which seems to exist, in the design of graphical equalizers, to choose channel-frequencies that are approximately spaced one octave apart, yet which will produce numbers that ‘look clean’ in decimal. For example, a sequence of frequencies is possible that goes 150 Hz, 300 Hz, 600 Hz, 1.2 kHz, 2.4 kHz, 5 kHz, 10 kHz, 20 kHz, resulting in an 8-band equalizer. Notably, in this example, 2.4 kHz will be treated as if it was 2.5 kHz as well, so that the next-higher band, at 5 kHz, will seem to be an exact octave higher.
This will not work as well, with a 20-band equalizer.
(Edit 03/26/2017 : )
Also, the difference between 2.4 and 2.5 is less than 1/20. Anything further-off will produce a hot-spot. So below 150 Hz, we might be ill-advised to put 80 instead of 75, because they would be too close by more than 1/20. I would actually suggest, 76 – 38 – 20 . Mind you, that 20 Hz suggestion would be off by 1/19, but who hears those frequencies so accurately anyway?