A146439 - OEIS

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A146439 as a simple table

n	a(n)
1	1
2	1
3	1
4	1
5	1
6	1
7	1
8	1
9	17
10	17
11	57
12	57
13	337
14	337
15	4357
16	4357
17	135183
18	135183
19	3521533
20	3521533
21	135176521
22	135176521
23	9933992919

[1,1,1,1,1,1,1,1,17,17,57,57,337,337,4357,4357, 135183,135183,3521533,3521533,135176521,135176521, 9933992919]