# A033280 (b-file synthesized from sequence entry)
0 1
1 27
2 385
3 4004
4 34398
5 259896
6 1790712
7 11511720
8 70114902
9 409003595
10 2303105805
11 12593413560
12 67173369900
13 350777861280
14 1798432526880
15 9073909567440
16 45140379405030
17 221768094898350
18 1077403874372826
19 5182007298602904
20 24699073588138180
21 116759256962107760