# A006657 (b-file synthesized from sequence entry)
2 2
3 12
4 84
5 640
6 5236
7 45164
8 406012
9 3772008
10 35994184
11 351173328
12 3490681428
13 35253449296
14 360946635312
15 3739935635756
16 39159200588780
17 413836299216608
18 4409705753032648
19 47337525317450816
20 511563350415103008