# A004383 (b-file synthesized from sequence entry)
2 1
3 24
4 496
5 9880
6 194580
7 3819816
8 74974368
9 1473109704
10 28987537150
11 571350360240
12 11279926456656
13 223044792457760
14 4416904685676756
15 87586833265107120
16 1739040916651368000
17 34569147570568156800