N=30
1: 2 6 10 0
2: 1 3 0
3: 2 4 0
4: 3 5 0
5: 4 6 0
6: 5 1 0
7: 8 9 10 0
8: 7 9 0
9: 8 7 0
10: 1 7 0
11: 12 16 20 0
12: 11 13 0
13: 12 14 0
14: 13 15 0
15: 14 16 0
16: 15 11 0
17: 18 19 20 0
18: 17 19 0
19: 18 17 0
20: 11 17 0
21: 22 26 30 0
22: 21 23 0
23: 22 24 0
24: 23 25 0
25: 24 26 0
26: 25 21 0
27: 28 29 30 0
28: 27 29 0
29: 28 27 0
30: 21 27 0
