A204430 - OEIS

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A204430 as a simple table

n	a(n)
1	1
2	2
3	9
4	34
5	144
6	1032
7	6936
8	48816
9	530712
10	5005152
11	50015232
12	707802624
13	8714718720
14	112586112000
15	1938416832000
16	29588291712000
17	469224244224000
18	9509523337728000
19	173318541516288000
20	3261008730405888000

[1,2,9,34,144,1032,6936,48816,530712,5005152, 50015232,707802624,8714718720,112586112000, 1938416832000,29588291712000,469224244224000, 9509523337728000,173318541516288000, 3261008730405888000]