1	1	0.5
2	2	1
3	4	1.5
4	8	2
5	15	2.46875
6	29	2.921875
7	55	3.3515625
8	105	3.76171875
9	201	4.154296875
10	383	4.5283203125
11	733	4.88623046875
12	1401	5.228271484375
13	2678	5.55517578125
14	5119	5.86761474609375
15	9784	6.16619873046875
16	18701	6.4515533447265625
17	35738	6.724212646484375
18	68307	6.984783172607422
19	130554	7.233795166015625
20	249518	7.47175407409668
21	476910	7.699162483215332
22	911526	7.916487216949463