# A216820 (b-file synthesized from sequence entry)
4 1
5 0
6 2
7 4
8 12
9 32
10 110
11 340
12 1209
13 4272
14 16166
15 61848
16 246660
17 1004883
18 4209124
19 18020832
20 78898047
21 352437205
22 1605225878
23 7445515638
24 35142033027
25 168644213617
26 822311934788
27 4071431204506
28 20457850555113