# A037184 (b-file synthesized from sequence entry)
3 6
4 48
5 420
6 3840
7 38010
8 407904
9 4739112
10 59405760
11 800309070
12 11542072080
13 177536452236
14 2902434644928
15 50271450894210
16 919799178083520
17 17730187503894480
18 359183503307677824
19 7629999730919490582
20 169605272611054951920
21 3937616869933172881140