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A021015
as a simple table
n
a(n)
0
0
1
9
2
0
3
9
4
0
5
9
6
0
7
9
8
0
9
9
10
0
11
9
12
0
13
9
14
0
15
9
16
0
17
9
18
0
19
9
20
0
21
9
22
0
23
9
24
0
25
9
26
0
[0,9,0,9,0,9,0,9,0,9,0,9,0,9,0,9,0,9,0,9,0,9,0,9, 0,9,0]