A020548 - OEIS

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A020548 as a simple table

n	a(n)
0	-1
1	-1
2	9
3	649
4	51841
5	6825601
6	1489881601
7	511943846401
8	262183528857601
9	191138113268121601
10	191138824350351360001
11	254405870811372994560001
12	439613359905259699568640001
13	965830554503712299093852160001

[-1,-1,9,649,51841,6825601,1489881601, 511943846401,262183528857601,191138113268121601, 191138824350351360001,254405870811372994560001, 439613359905259699568640001, 965830554503712299093852160001]