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A001691 as a simple table

na(n)
10
21
39
4108
53420
6114480
77786800
8497266560
942616445760
104320959126400
11534444478444800
1277699101730342400
1313282131639801024000

[0,1,9,108,3420,114480,7786800,497266560,
 42616445760,4320959126400,534444478444800,
 77699101730342400,13282131639801024000]