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A172854 as a simple table

na(n)
10
20
321
4305872
550984927470
647703798786066840
7209367461452656000222414
83715952487541217998469935646848
9235540792783974946951038854447958540420
1048023201408596246269169102263301826304599932800

[0,0,21,305872,50984927470,47703798786066840,
 209367461452656000222414,
 3715952487541217998469935646848,
 235540792783974946951038854447958540420,
 48023201408596246269169102263301826304599932800]