# A012709 (b-file synthesized from sequence entry)
0 1
1 1
2 3
3 12
4 57
5 340
6 2305
7 18186
8 158977
9 1560840
10 16695553
11 196272142
12 2483596577
13 34036624700
14 497515462561
15 7792454528002
16 129248702613505
17 2278494692749840
18 42291311707716609
19 828953188249846678