# A074581 (b-file synthesized from sequence entry)
0 0
1 2
2 13
3 81
4 504
5 3136
6 19513
7 121415
8 755476
9 4700770
10 29249425
11 181997601
12 1132436852
13 7046319384
14 43844049029
15 272809183135
16 1697490356184
17 10562230626642
18 65720971788709
19 408933139743937
20 2544489349890656