# A003760 (b-file synthesized from sequence entry)
1 2
2 40
3 240
4 1558
5 8300
6 43438
7 212700
8 1014700
9 4691580
10 21257258
11 94520524
12 414149254
13 1791339472
14 7664373014
15 32481662616
16 136520499746
17 569599125312
18 2361080470268
19 9730117780704
20 39888323454064