generate custumize Linspace for x axis

Hi,

I want to create a linspace with the following description I have a vector of N (N=160) values of some coefficients; the X axis ranges from 0 to N; the X axis varies by 2^i; where i is a natural number; I want to creat a linspace from 0 to N with 75 elements; exemple of x axis between 2 and 4 I have 12 elenemts; between 4 and 8 => 12 elements; between 8 and 16 => 12 elements, an so on;