A012230 - OEIS

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A012230 as a simple table

n	a(n)
0	1
1	-1
2	21
3	-1101
4	109001
5	-17491001
6	4139085981
7	-1355308485701
8	586612833746961
9	-324261948714025201
10	222851423174495787941
11	-186365710421614910029501
12	186332939048243649892744921

[1,-1,21,-1101,109001,-17491001,4139085981, -1355308485701,586612833746961, -324261948714025201,222851423174495787941, -186365710421614910029501, 186332939048243649892744921]