# A047038 (b-file synthesized from sequence entry)
0 1
1 4
2 15
3 56
4 209
5 784
6 2958
7 11220
8 42753
9 163548
10 627770
11 2416804
12 9328384
13 36087780
14 139890764
15 543246696
16 2113015731
17 8230687548
18 32102370550
19 125358442460
20 490049744789
21 1917595810240
22 7510507532319
23 29440544167696