# A369503 (b-file synthesized from sequence entry)
0 1
1 4
2 24
3 168
4 1284
5 10384
6 87360
7 756704
8 6703168
9 60444928
10 552990592
11 5120101760
12 47887472000
13 451759449600
14 4293634467840
15 41073654689280
16 395170166443008
17 3821262491103232
18 37118973530660864
19 362035991963869184
20 3544080121528001536