# A049070 (b-file synthesized from sequence entry)
0 0
1 2
2 27
3 224
4 1500
5 8910
6 49049
7 256256
8 1288872
9 6298500
10 30093910
11 141210432
12 652860520
13 2981331990
14 13472983125
15 60343756800
16 268187306640
17 1183875281820
18 5194996380090
19 22676052360000
20 98513956031400
21 426171522716940
22 1836562780483002