A248838 - OEIS

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A248838 as a simple table

n	a(n)
1	2
2	6
3	24
4	120
5	718
6	4994
7	39556
8	351320
9	3456742
10	37314126
11	438366374
12	5567209930
13	75995663398
14	1109556555434
15	17252609166736
16	284620418911180
17	4965138989585412
18	91317809653363376
19	1765937111915469414

[2,6,24,120,718,4994,39556,351320,3456742, 37314126,438366374,5567209930,75995663398, 1109556555434,17252609166736,284620418911180, 4965138989585412,91317809653363376, 1765937111915469414]