Perlin Noise

What scale factor must be applied to Perlin noise in order that the resulting noise fully occupy the range $[0,1]?$ Assume that a $=$ b $=4$ and that $3$ levels of noise are summed, and that the original noise is in the range $[0,1].$

The scale factor divides the Perlin noise sum $($e$.$g$.$ a scale factor of $2$ would divide the sum by $2).$

Enter an exact decimal number, including any necessary digits after the decimal point.