# A113888 (b-file synthesized from sequence entry)
0 6
1 84
2 1200
3 17325
4 252252
5 3699696
6 54609984
7 810616950
8 12092280200
9 181176906768
10 2725140250560
11 41132585656890
12 622787147955000
13 9456196695480000
14 143946539451475200
15 2196309308974461450
16 33581927605139911800
17 514470608092210770000
18 7895695609776494520000