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A030446
as a simple table
n
a(n)
1
1
2
1
3
6
4
35
5
290
6
2680
7
26379
8
267598
9
2758016
10
28749456
11
302120154
12
3196299285
13
34007337629
[1,1,6,35,290,2680,26379,267598,2758016,28749456, 302120154,3196299285,34007337629]