# A002546 (b-file synthesized from sequence entry)
1 1
2 2
3 4
4 8
5 15
6 240
7 15120
8 672
9 8400
10 100800
11 69300
12 4950
13 17199000
14 22422400
15 33633600
16 201801600
17 467812800
18 102918816000
19 410646075840
20 3555377280
21 215100325440
22 5162407810560
23 30920671782000
24 190281057120
25 1085315579548200
26 562756226432400
27 22969641895200