A146250 - OEIS

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A146250 as a simple table

n	a(n)
1	1
2	1
3	1
4	1
5	1
6	1
7	3
8	3
9	9
10	9
11	21
12	21
13	85
14	85
15	755
16	755
17	7735
18	7735
19	87315
20	87315
21	1464567
22	1464567
23	39342833
24	39342833
25	1394115639
26	1394115639
27	64760833633
28	64760833633
29	4237428548705
30	4237428548705

[1,1,1,1,1,1,3,3,9,9,21,21,85,85,755,755,7735, 7735,87315,87315,1464567,1464567,39342833, 39342833,1394115639,1394115639,64760833633, 64760833633,4237428548705,4237428548705]