# A306946 (b-file synthesized from sequence entry)
0 1
1 1
2 2
3 6
4 30
5 150
6 900
7 6300
8 52920
9 516600
10 5166000
11 56826000
12 689396400
13 9135126000
14 127891764000
15 1918376460000
16 32083427376000
17 547888316976000
18 9941031356256000
19 188879595768864000
20 3817981890122400000
21 80266319244951840000
22 1769328161437636800000