A030238 - OEIS

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A030238 as a simple table

n	a(n)
0	1
1	1
2	3
3	7
4	20
5	59
6	184
7	593
8	1964
9	6642
10	22845
11	79667
12	281037
13	1001092
14	3595865
15	13009673
16	47366251
17	173415176
18	638044203
19	2357941142
20	8748646386
21	32576869203
22	121701491701
23	456012458965
24	1713339737086

[1,1,3,7,20,59,184,593,1964,6642,22845,79667, 281037,1001092,3595865,13009673,47366251, 173415176,638044203,2357941142,8748646386, 32576869203,121701491701,456012458965, 1713339737086]