The ratios are .75|1|1.33|1.5|2.|3.|4. (or 3:4:6:8:12:16) That is, for your 10x10px bitmap, the graphics would be
ldpi - 10x10 * 0.75 = 7x7
mdpi - 10x10 * 1 = 10x10
tvdpi - 10x10 * 1.33 = 13x13
hdpi - 10x10 * 1.5 = 15x15
xhdpi - 10x10 * 2 = 20x20
xxhdpi - 10x10 * 3 = 30x30
xxxhdpi - 10x10 * 4 = 40x40
