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A009160 as a simple table

na(n)
01
12
220
3448
417296
51013600
683547584
79196867072
81301697829120
9230093807905280
1049636887216382976
1112825384465418534912
123908078275606800338944
131386160615200497825275904

[1,2,20,448,17296,1013600,83547584,9196867072,
 1301697829120,230093807905280,49636887216382976,
 12825384465418534912,3908078275606800338944,
 1386160615200497825275904]