# A110376 (b-file synthesized from sequence entry)
1 1
2 2
3 9
4 32
5 250
6 864
7 12348
8 67584
9 804816
10 5760000
11 116915040
12 686776320
13 19323757440
14 157991178240
15 2951575200000
16 42301705420800
17 1202482800691200
18 10048607738265600
19 425162773111910400
20 4541227794432000000