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A056270 as a simple table

na(n)
10
20
30
40
5120
61800
716800
8126000
9834120
105102880
1129607600
12165526200
13901020120
144808987400
1525292030280
16131542740000
17678330198120
183474970629480
1917710714165200
2089904725757000

[0,0,0,0,120,1800,16800,126000,834120,5102880,
 29607600,165526200,901020120,4808987400,
 25292030280,131542740000,678330198120,
 3474970629480,17710714165200,89904725757000]