# A107389 (b-file synthesized from sequence entry)
0 0
1 1
2 -1
3 2
4 5
5 31
6 144
7 697
8 3335
9 15986
10 76589
11 366967
12 1758240
13 8424241
14 40362959
15 193390562
16 926589845
17 4439558671
18 21271203504
19 101916458857
20 488311090775
21 2339638995026
22 11209883884349
23 53709780426727
24 257339018249280
25 1232985310819681
26 5907587535849119