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A220871
as a simple table
n
a(n)
1
1
2
1
3
2
4
4
5
10
6
26
7
76
8
232
9
756
10
2548
11
8906
12
31846
13
116422
14
432758
15
1634944
[1,1,2,4,10,26,76,232,756,2548,8906,31846,116422, 432758,1634944]