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A021103
as a simple table
n
a(n)
0
0
1
0
2
0
3
1
4
3
5
9
6
44
7
294
8
2893
9
36496
10
545808
11
9029737
12
159563559
13
2952794985
14
56589742050
[0,0,0,1,3,9,44,294,2893,36496,545808,9029737, 159563559,2952794985,56589742050]