# A337010 (b-file synthesized from sequence entry)
0 1
1 4
2 18
3 92
4 532
5 3440
6 24552
7 191280
8 1612304
9 14597952
10 141123872
11 1449324992
12 15743376704
13 180203389696
14 2166381979264
15 27274611880704
16 358690234163456
17 4916123783848960
18 70076765972288000
19 1036967662211324928
20 15902394743591408640