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A003189
as a simple table
n
a(n)
1
1
2
1
3
1
4
2
5
6
6
156
7
7013488
8
29288387523484992
9
234431745534048922731115019069056
[1,1,1,2,6,156,7013488,29288387523484992, 234431745534048922731115019069056]