A121813 - OEIS

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A121813 as a simple table

n	a(n)
1	0
2	1
3	1
4	1
5	1
6	4
7	13
8	121
9	8401
10	17724001
11	19980403610080
12	3017939125082738100693961
13	1069257489122187637992525695378883464262898201

[0,1,1,1,1,4,13,121,8401,17724001,19980403610080, 3017939125082738100693961, 1069257489122187637992525695378883464262898201]