Well, to start with; the fraction 3/1 = 3, not .33
2nd, That scale was for increasing in frequency. You are wanting to decrease in frequency by one-half octave; not increase.
So, if an octave higher is represented as 2/1, then an octave lower would be the reciprocal of that, or 1/2. Now, you are wanting to find 1/2 of that 1/2; or more easily, 1/4. So, you could take that 60hz and subtract 1/4, or (more quickly) mulitply it by 3/4.
So, one octave lower than 60hz is 45hz. To verify this; one octave lower from 60hz is 30hz. The middle point between those is 45hz.
Correct me if I'm wrong, but that's just using logic.