# A002920 (b-file synthesized from sequence entry)
0 1
1 6
2 30
3 138
4 606
5 2586
6 10818
7 44574
8 181542
9 732678
10 2935218
11 11687202
12 46296210
13 182588850
14 717395262
15 2809372302
16 10969820358
17 42724062966
18 166015496838
19 643768299018
20 2491738141314
21 9628130289018
22 37146098272266
23 143110933254702
24 550643544948090