# A336310 (b-file synthesized from sequence entry)
0 0
1 0
2 2
3 24
4 300
5 4260
6 69120
7 1271340
8 26233200
9 601246800
10 15171105600
11 418203324000
12 12509695598400
13 403696590897600
14 13982667790291200
15 517482647165484000
16 20381726051118432000
17 851302665544050720000
18 37587618060140244096000
19 1749369290830388555328000
20 85599487854917373617280000