# A251684 (b-file synthesized from sequence entry)
0 1
1 2
2 5
3 16
4 69
5 426
6 3947
7 55612
8 1177747
9 36816650
10 1676270109
11 110202314208
12 10408422663015
13 1407329003121294
14 271801891072128621
15 74846096423770137324
16 29351301902680241116593
17 16374214768286861089202358
18 12985582377076992552497257703
19 14629438237685095017820000611400