A020109 - OEIS

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A020109 as a simple table

n	a(n)
0	1
1	1
2	2
3	5
4	19
5	93
6	544
7	3742
8	29514
9	262342
10	2594262
11	28248628
12	335844793
13	4328666216
14	60120364101
15	895125421054
16	14222548356739
17	240203038913808
18	4296965473902564
19	81164903395937307
20	1614279745319197539

[1,1,2,5,19,93,544,3742,29514,262342,2594262, 28248628,335844793,4328666216,60120364101, 895125421054,14222548356739,240203038913808, 4296965473902564,81164903395937307, 1614279745319197539]