# A005770 (b-file synthesized from sequence entry)
5 1
6 9
7 55
8 286
9 1362
10 6143
11 26729
12 113471
13 473471
14 1951612
15 7974660
16 32384127
17 130926391
18 527657073
19 2121795391
20 8518575466
21 34162154550
22 136893468863
23 548253828965
24 2194897467395
25 8784784672511
26 35153438973304
27 140653028240520
28 562719731644671