Probably this solution is more easily implemented in VHDL, but,
If you can settle for pseudo-random numbers (which is, they change all the time but the sequence is repeatable from a given starting point), you can go for a shift register-based pseudo random generator (link on the image):
See also this alternative page
You can extend it to the number of bits that you require at the output, but make sure that the XOR "scrambles" the bits so as it doesn't fall into a loop with a limited number of different output sequences.
Here there is a tool to generate CRC (Cyclic Redundancy Code?) in VHDL and Verilog, and it's also discussed here