# A117581 (b-file synthesized from sequence entry)
1 2
2 9
3 81
4 4375
5 9801
6 123201
7 336141
8 11859211
9 11859211
10 177182721
11 1611308700
12 3463200000
13 63927525376
14 421138799640
15 1109496723126
16 1453579866025
17 20628591204481
18 31887350832897
19 31887350832897
20 119089041053697