# A074002 (b-file synthesized from sequence entry)
1 0
2 0
3 6
4 6
5 30
6 72
7 252
8 756
9 2106
10 6642
11 19602
12 59292
13 176904
14 530712
15 1596510
16 4780782
17 14351094
18 43040160
19 129146724
20 387440172
21 1162202418