scale steps repeat in both directions

f = base frequency

(f * 2) and (f/2) sound so much like f that it is necessary to number the steps between f and f*2 only

step frequency
7 1500 octave 3
6 1333
5 1200
4 1066
3 1000
2 900
1 800
7 750 octave 2
6 666
5 600
4 533
3 500
2 450
1 400
7 375 octave 1
6 333
5 300
4 266
3 250
2 225
1 200

octave = 7 scale steps

f sounds so much like f * 2 because it is mathematically so similar (put image of two sine waves here - f and f * 2)