# A027147 (b-file synthesized from sequence entry)
2 1
3 12
4 56
5 480
6 2040
7 16576
8 69888
9 557568
10 2361600
11 18675712
12 79613952
13 626409472
14 2686867456
15 21071708160
16 90875494400
17 711081984000
18 3081088991232
19 24069137760256
20 104712901754880
21 816979824869376
22 3566715303624704
23 27800440481513472
24 121738713372819456
25 948129286114508800