# A090755 (b-file synthesized from sequence entry)
0 1
1 1
2 2
3 6
4 24
5 40
6 720
7 5040
8 13440
9 362880
10 3628800
11 13305600
12 479001600
13 889574400
14 29059430400
15 1307674368000
16 1609445376000
17 118562476032000
18 6402373705728000
19 121645100408832000
20 115852476579840000