# A013168 (b-file synthesized from sequence entry)
0 1
1 2
2 4
3 9
4 24
5 97
6 534
7 3647
8 27272
9 232345
10 2170874
11 22882827
12 260563908
13 3272680621
14 43811275382
15 637916495327
16 9816624434928
17 162606798592913
18 2827858695802930
19 52505736635681875
20 1018209224687676028