A146590 - OEIS

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A146590 as a simple table

n	a(n)
1	1
2	1
3	1
4	1
5	1
6	1
7	1
8	5
9	13
10	25
11	41
12	73
13	405
14	2087
15	9095
16	31781
17	109905
18	706437
19	6193961
20	52066515
21	395176419
22	2801856537
23	27230658787

[1,1,1,1,1,1,1,5,13,25,41,73,405,2087,9095,31781, 109905,706437,6193961,52066515,395176419, 2801856537,27230658787]