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A140088
as a simple table
n
a(n)
0
0
1
0
2
0
3
1
4
6
5
24
6
78
7
368
8
1902
9
11062
10
77426
11
692414
12
6261624
13
68889928
14
764874856
15
9274470290
[0,0,0,1,6,24,78,368,1902,11062,77426,692414, 6261624,68889928,764874856,9274470290]