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A215971
as a simple table
n
a(n)
1
1
2
1
3
2
4
4
5
9
6
20
7
48
8
115
9
286
10
717
11
1815
12
4574
13
11505
14
28546
15
69705
16
166010
[1,1,2,4,9,20,48,115,286,717,1815,4574,11505, 28546,69705,166010]