# A068589 (b-file synthesized from sequence entry)
1 1
2 4
3 36
4 144
5 3600
6 1200
7 58800
8 235200
9 6350400
10 6350400
11 768398400
12 768398400
13 129859329600
14 129859329600
15 129859329600
16 519437318400
17 150117385017600
18 50039128339200
19 18064125330451200
20 18064125330451200
21 54192375991353600