# A090115 (b-file synthesized from sequence entry)
1 1
2 1
3 4
4 15
5 252
6 924
7 11440
8 43758
9 497420
10 13123110
11 54627300
12 1251677700
13 12033222880
14 52860229080
15 511738760544
16 10363194502115
17 197548686920970
18 925029565741050
19 17302625882942400
20 161884603662657876