# A111989 (b-file synthesized from sequence entry)
0 1
1 6
2 36
3 208
4 1200
5 6912
6 39808
7 229248
8 1320192
9 7602688
10 43782144
11 252131328
12 1451966464
13 8361541632
14 48152199168
15 277297463296
16 1596892446720
17 9196137086976
18 52958442815488
19 304975517319168
20 1756284007219200