# A009624 (b-file synthesized from sequence entry)
0 0
1 1
2 2
3 4
4 16
5 56
6 288
7 1576
8 9920
9 70912
10 541184
11 4668544
12 42274816
13 423673472
14 4449451776
15 50674728448
16 605255720960
17 7717401038848
18 103187353223168
19 1456461190426624
20 21528004660707328
21 333308651379949568