# A138113 (b-file synthesized from sequence entry)
1 1
2 2
3 6
4 24
5 120
6 720
7 5040
8 27720
9 166320
10 1441440
11 7207200
12 73513440
13 367567200
14 4655851200
15 64250746560
16 1028011944960
17 5140059724800
18 32607253879200
19 260858031033600
20 4620913692595200
21 97039187544499200
22 897612484786617600
23 9873737332652793600