# A306947 (b-file synthesized from sequence entry)
0 1
1 1
2 3
3 9
4 48
5 240
6 1620
7 11340
8 103320
9 929880
10 9865800
11 108523800
12 1362160800
13 17708090400
14 253361908800
15 3800428632000
16 63340477200000
17 1076788112400000
18 19769829743664000
19 375626765129616000
20 7640832869429760000
21 160457490258024960000
22 3559701523615997760000