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A173110
as a simple table
n
a(n)
0
1
1
1
2
3
3
6
4
20
5
60
6
230
7
950
8
4420
9
22230
10
120914
11
702820
12
4343860
13
28393280
14
195492054
[1,1,3,6,20,60,230,950,4420,22230,120914,702820, 4343860,28393280,195492054]