A146717 - OEIS

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A146717 as a simple table

n	a(n)
1	1
2	1
3	1
4	1
5	1
6	5
7	17
8	39
9	155
10	745
11	4705
12	39573
13	369483
14	3970963
15	54943873
16	950039207
17	20417177215
18	545483266919
19	17663079620537
20	695250063366563
21	33778790635375371

[1,1,1,1,1,5,17,39,155,745,4705,39573,369483, 3970963,54943873,950039207,20417177215, 545483266919,17663079620537,695250063366563, 33778790635375371]