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A057402 as a simple table

na(n)
01
10
20
30
4-4
50
6-24
7-32
8-120
9-336
10-768
11-2496
12-6612
13-17296
14-61176
15-150016
16-518308
17-1418576
18-4266064
19-12800864
20-36773692
21-112996720
22-334128168
23-1009728992
24-3068945888
25-9160795472
26-27959064832

[1,0,0,0,-4,0,-24,-32,-120,-336,-768,-2496,-6612,
 -17296,-61176,-150016,-518308,-1418576,-4266064,
 -12800864,-36773692,-112996720,-334128168,
 -1009728992,-3068945888,-9160795472,-27959064832]