Below is a simulator for a zipfian distribution with parameters $N$ and $\alpha$. Each entry has probability: $${f(i;\alpha,N)~=~{\frac {\left[{\frac {1}{\ i^{\alpha}\ }}\right]}{\ \left[\ \sum \limits _{n=1}^{N}{\frac {1}{\ n^{\alpha}\ }}\ \right]\ \ }}}$$