3x3 <r2,U,D> gods algorithm

depth   states
0       1
1       7
2       21
3       60
4       189
5       549
6       1645
7       4563
8       12951
9       36824
10      103156
11      290829
12      807327
13      2229409
14      6057997
15      16078344
16      41290101
17      99325713
18      214996427
19      380326032
20      469048087
21      316226485
22      74795308
23      4034820
24      35165
25      357
26      25
27      7
28      1
29      0