# A174774 (b-file synthesized from sequence entry)
1 0
2 1
3 3
4 30
5 130
6 780
7 3696
8 19768
9 97560
10 510660
11 2603260
12 13754136
13 72333768
14 390339040
15 2116922640
16 11722194240
17 65521880896
18 372897624528
19 2146502657520
20 12558129505120
21 74371827119520
22 447090649997376