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A143889
as a simple table
n
a(n)
0
1
1
2
2
7
3
33
4
202
5
1671
6
17279
7
234724
8
4081665
9
92343898
10
2711730350
11
103991393887
12
5218390436191
[1,2,7,33,202,1671,17279,234724,4081665,92343898, 2711730350,103991393887,5218390436191]