# A028498 (b-file synthesized from sequence entry)
0 1
1 4
2 24
3 186
4 1770
5 19980
6 260820
7 3863160
8 63980280
9 1171195200
10 23476068000
11 511296786000
12 12021166357200
13 303414507396000
14 8182057223340000
15 234753130435824000
16 7139815170664176000
17 229442416696164672000
18 7767967204994540544000
19 276345182709766890720000