A054093 - OEIS

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A054093 as a simple table

n	a(n)
1	1
2	2
3	2
4	8
5	24
6	106
7	546
8	3368
9	24032
10	195170
11	1777650
12	17950552
13	199059672
14	2405063018
15	31448531954
16	442501797656
17	6666753146496
18	107081325959938
19	1826636018849442

[1,2,2,8,24,106,546,3368,24032,195170,1777650, 17950552,199059672,2405063018,31448531954, 442501797656,6666753146496,107081325959938, 1826636018849442]