A075220 - OEIS

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A075220 as a simple table

n	a(n)
1	1
2	1
3	1
4	3
5	4
6	12
7	21
8	56
9	111
10	261
11	462
12	1431
13	1875
14	4696
15	9410
16	20099
17	24034
18	77884
19	79925
20	266786
21	358096
22	658594
23	796571
24	3227163
25	2980476
26	6268017
27	10167660
28	24321735
29	21477012
30	85964698

[1,1,1,3,4,12,21,56,111,261,462,1431,1875,4696, 9410,20099,24034,77884,79925,266786,358096,658594, 796571,3227163,2980476,6268017,10167660,24321735, 21477012,85964698]