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A012254 as a simple table

na(n)
01
11
21
32
45
524
6109
7720
84521
940320
10330681
113628800
1236468717
13479001600
145721101541
1587178291200
161205289090513
1720922789888000
18328897528901361
196402373705728000
20112769846051251797
212432902008176640000

[1,1,1,2,5,24,109,720,4521,40320,330681,3628800,
 36468717,479001600,5721101541,87178291200,
 1205289090513,20922789888000,328897528901361,
 6402373705728000,112769846051251797,
 2432902008176640000]