A221783 - OEIS

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A221783 as a simple table

n	a(n)
1	0
2	3
3	5
4	16
5	41
6	105
7	288
8	735
9	1981
10	5156
11	13685
12	35973
13	94940
14	250271
15	659721
16	1739740
17	4585933
18	12092245
19	31878636
20	84050611
21	221594145
22	584232168
23	1540316025

[0,3,5,16,41,105,288,735,1981,5156,13685,35973, 94940,250271,659721,1739740,4585933,12092245, 31878636,84050611,221594145,584232168,1540316025]