# A227467 (b-file synthesized from sequence entry)
0 1
1 1
2 4
3 24
4 252
5 3660
6 73560
7 1921080
8 63411600
9 2574406800
10 125747475840
11 7258472907840
12 487590023511360
13 37629962101892160
14 3299990581104497280
15 325758967714868688000
16 35904380354917794720000
17 4387164775718671231084800
18 590610815931660911894707200
19 87118296156852814044256665600