# A003291 (b-file synthesized from sequence entry)
2 2
3 6
4 16
5 46
6 140
7 464
8 1580
9 5538
10 19804
11 71884
12 264204
13 980778
14 3671652
15 13843808
16 52519836
17 200320878
18 767688176
19 2954410484
20 11412815256
21 44237340702
22 171997272012
23 670612394118
24 2621415708492
25 10271274034254