My solution for 11 persons on 45 occasions is as follows:--

2 11 9 4 7 6 5 1 8 3 10

2 1 11 7 6 3 10 8 5 4 9

2 11 10 3 9 4 8 5 1 7 6

2 11 5 8 1 3 10 6 7 9 4

2 11 1 10 3 4 9 6 7 5 8

There are two repeaters, 1 and 2, and the cycle is, 3, 4, 5,... 11. We

thus get 5 groups of 9 lines each.