artist_id keyword_id
1 3
1 2
1 14
2 3
2 7
2 8
2 9
3 2
3 54
3 14
4 54
4 10
5 9
5 54

how can i count(sum) the number of instances of each keyword_id, and output the number of times each occurs with another when associated with a given artist_id?

i.e
3= 1 instance
14= 2 instances
etc
54= 3 instances

and
54 with 10 = 1 instances
54 with 9 = 1 instances
etc

eventually
so
54, 10, 9, 106 = 2 instances
3, 7, 8, 19 = 14 instances

i am using mysql and php for a digital sound art project

any ideas?
thanks