# A355989 (b-file synthesized from sequence entry)
2 1
3 3
4 6
5 30
6 60
7 420
8 840
9 7560
10 15120
11 166320
12 332640
13 4324320
14 8648640
15 129729600
16 259459200
17 4410806400
18 8821612800
19 167610643200
20 335221286400
21 7039647014400
22 14079294028800
23 323823762662400
24 647647525324800
25 16191188133120000
26 32382376266240000