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A074001
as a simple table
n
a(n)
1
0
2
2
3
0
4
12
5
30
6
72
7
252
8
702
9
2268
10
6480
11
19602
12
59292
13
176904
14
532170
15
1592136
16
4785156
[0,2,0,12,30,72,252,702,2268,6480,19602,59292, 176904,532170,1592136,4785156]