# A256880 (b-file synthesized from sequence entry)
1 1
2 4
3 9
4 48
5 200
6 1440
7 8820
8 80640
9 653184
10 7257600
11 73180800
12 958003200
13 11564467200
14 174356582400
15 2451889440000
16 41845579776000
17 671854030848000
18 12804747411456000
19 231125690776780800
20 4865804016353280000