# A002302 (b-file synthesized from sequence entry)
3 2
4 16
5 136
6 1232
7 12096
8 129024
9 1491840
10 18627840
11 250145280
12 3597834240
13 55212917760
14 900842342400
15 15575854694400
16 284549942476800
17 5477586392678400
18 110832202594713600
19 2351805274570752000