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A012268
as a simple table
n
a(n)
0
0
1
0
2
2
3
6
4
22
5
100
6
788
7
8568
8
103416
9
1307808
10
17722512
11
264361680
12
4373968080
[0,0,2,6,22,100,788,8568,103416,1307808,17722512, 264361680,4373968080]