# A164872 (b-file synthesized from sequence entry)
1 1
2 2
3 6
4 24
5 120
6 718
7 4884
8 35546
9 264590
10 1969912
11 14560996
12 106781758
13 778073440
14 5643649364
15 40811356112
16 294554236798
17 2123419108962
18 15296729408614
19 110149122090326
20 792974948890068
21 5707931771206042