A269633 - OEIS

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A269633 as a simple table

n	a(n)
1	1
2	9
3	21
4	93
5	381
6	6596
7	20995
8	24573
9	57823
10	62359
11	98756
12	208148
13	393213
14	400844
15	405788
16	418756
17	1572861
18	6460508

[1,9,21,93,381,6596,20995,24573,57823,62359,98756, 208148,393213,400844,405788,418756,1572861, 6460508]