I couldn't resist programming it. I have a MATLAB function randchoiceseq(N,P,Q,K), where N, P, and Q are as above and K is the length of sequence to generate. If it would be useful for the horoscope site, I can send a copy. Result of randchoiceseq(33,16,40,100):

 8 16 19 18 5 2 15 33 28 1 25 24 26 31 32 10 4 27 20 7
3 16 23 6 33 17 22 13 21 12 14 30 9 19 29 8 11 2 5 18
15 28 25 4 24 26 1 10 32 31 27 3 20 7 16 33 23 19 17 6
13 8 22 21 12 14 30 29 9 25 15 5 2 11 18 28 26 24 32 4
27 1 20 10 3 31 33 23 7 16 17 19 13 29 6 8 14 24 22 21