# A074003 (b-file synthesized from sequence entry)
1 1
2 0
3 3
4 9
5 30
6 81
7 225
8 756
9 2187
10 6561
11 19602
12 59049
13 176904
14 532170
15 1596510
16 4785156
17 14351094
18 43053282
19 129146724
20 387400806