A012921 - OEIS

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A012921 as a simple table

n	a(n)
0	1
1	4
2	16
3	184
4	8320
5	529824
6	52633728
7	7595502464
8	1487529832448
9	380497987834368
10	123182327672588288
11	49234752596303947776
12	23812565081465676070912
13	13707078729819239829938176

[1,4,16,184,8320,529824,52633728,7595502464, 1487529832448,380497987834368,123182327672588288, 49234752596303947776,23812565081465676070912, 13707078729819239829938176]