A181858 - OEIS

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A181858 as a simple table

n	a(n)
0	1
1	1
2	1
3	1
4	1
5	4
6	4
7	36
8	18
9	64
10	576
11	14400
12	43200
13	518400
14	518400
15	5080320
16	12700800
17	1625702400
18	1625702400
19	131681894400
20	131681894400
21	627056640000
22	13168189440000
23	1593350922240000

[1,1,1,1,1,4,4,36,18,64,576,14400,43200,518400, 518400,5080320,12700800,1625702400,1625702400, 131681894400,131681894400,627056640000, 13168189440000,1593350922240000]