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A028680 as a simple table

na(n)
01
1306
232023512
31089004102288704
412000667955029147591142400
542847968954950283704312619696092774400
649567873660106321460531697392097352394556112948428800

[1,306,32023512,1089004102288704,
 12000667955029147591142400,
 42847968954950283704312619696092774400,
 49567873660106321460531697392097352394556112948428\
 800]