A146866 - OEIS

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A146866 as a simple table

n	a(n)
1	1
2	1
3	1
4	1
5	1
6	9
7	25
8	67
9	375
10	1415
11	11011
12	122823
13	1158135
14	14699219
15	232067021
16	4207284521
17	106772232239
18	3295265497287
19	118967291277627
20	5362038267435757
21	294471642312195023
22	20044933173937086949

[1,1,1,1,1,9,25,67,375,1415,11011,122823,1158135, 14699219,232067021,4207284521,106772232239, 3295265497287,118967291277627,5362038267435757, 294471642312195023,20044933173937086949]