A121689 - OEIS

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A121689 as a simple table

n	a(n)
0	1
1	1
2	2
3	5
4	16
5	57
6	231
7	1023
8	4926
9	25483
10	140601
11	822422
12	5074015
13	32881868
14	223027542
15	1578435549
16	11625317128
17	88894615929
18	704269188135
19	5770209550496
20	48810504348082
21	425650324975153
22	3821377057170313

[1,1,2,5,16,57,231,1023,4926,25483,140601,822422, 5074015,32881868,223027542,1578435549,11625317128, 88894615929,704269188135,5770209550496, 48810504348082,425650324975153,3821377057170313]